[PATCH v7 0/6] rcu: Add RCU stall diagnosis information

[PATCH v7 0/6] rcu: Add RCU stall diagnosis information

[Zhen Lei]

v6 --> v7:
1. Use kcpustat_field() to obtain the cputime.
2. Make the output start with "\t" to match other related prints.
3. Aligns the output of the last line of RCU stall.

v5 --> v6:
1. When there are more than two continuous RCU stallings, correctly handle the
   value of the second and subsequent sampling periods. Update comments and
   document.
   Thanks to Elliott, Robert for the test.
2. Change "rcu stall" to "RCU stall".

v4 --> v5:
1. Resolve a git am conflict. No code change.

v3 --> v4:
1. Rename rcu_cpu_stall_deep_debug to rcu_cpu_stall_cputime.

v2 --> v3:
1. Fix the return type of kstat_cpu_irqs_sum()
2. Add Kconfig option CONFIG_RCU_CPU_STALL_DEEP_DEBUG and boot parameter
   rcupdate.rcu_cpu_stall_deep_debug.
3. Add comments and normalize local variable name


v1 --> v2:
1. Fixed a bug in the code. If the rcu stall is detected by another CPU,
   kcpustat_this_cpu cannot be used.
@@ -451,7 +451,7 @@ static void print_cpu_stat_info(int cpu)
        if (r->gp_seq != rdp->gp_seq)
                return;

-       cpustat = kcpustat_this_cpu->cpustat;
+       cpustat = kcpustat_cpu(cpu).cpustat;
2. Move the start point of statistics from rcu_stall_kick_kthreads() to
   rcu_implicit_dynticks_qs(), removing the dependency on irq_work.

v1:
In some extreme cases, such as the I/O pressure test, the CPU usage may
be 100%, causing RCU stall. In this case, the printed information about
current is not useful. Displays the number and usage of hard interrupts,
soft interrupts, and context switches that are generated within half of
the CPU stall timeout, can help us make a general judgment. In other
cases, we can preliminarily determine whether an infinite loop occurs
when local_irq, local_bh or preempt is disabled.

Zhen Lei (6):
  genirq: Fix the return type of kstat_cpu_irqs_sum()
  sched: Add helper kstat_cpu_softirqs_sum()
  sched: Add helper nr_context_switches_cpu()
  rcu: Add RCU stall diagnosis information
  doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information
  rcu: Align the output of RCU stall

 Documentation/RCU/stallwarn.rst               | 88 +++++++++++++++++++
 .../admin-guide/kernel-parameters.txt         |  6 ++
 include/linux/kernel_stat.h                   | 14 ++-
 kernel/rcu/Kconfig.debug                      | 11 +++
 kernel/rcu/rcu.h                              |  1 +
 kernel/rcu/tree.c                             | 18 ++++
 kernel/rcu/tree.h                             | 19 ++++
 kernel/rcu/tree_stall.h                       | 35 +++++++-
 kernel/rcu/update.c                           |  2 +
 kernel/sched/core.c                           |  5 ++
 10 files changed, 196 insertions(+), 3 deletions(-)

-- 
2.25.1

[PATCH v7 1/6] genirq: Fix the return type of kstat_cpu_irqs_sum()

[Zhen Lei]

The type of member irqs_sum is unsigned long, so kstat_cpu_irqs_sum()
should also return unsigned long. Otherwise, the value maybe truncated.

Fixes: f2c66cd8eedd ("/proc/stat: scalability of irq num per cpu")
Reported-by: Elliott, Robert (Servers) <elliott@hpe.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 include/linux/kernel_stat.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index ddb5a358fd829f4..90e2fdc17d79ff8 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -75,7 +75,7 @@ extern unsigned int kstat_irqs_usr(unsigned int irq);
 /*
  * Number of interrupts per cpu, since bootup
  */
-static inline unsigned int kstat_cpu_irqs_sum(unsigned int cpu)
+static inline unsigned long kstat_cpu_irqs_sum(unsigned int cpu)
 {
 	return kstat_cpu(cpu).irqs_sum;
 }
-- 
2.25.1

[PATCH v7 2/6] sched: Add helper kstat_cpu_softirqs_sum()

[Zhen Lei]

Similar to kstat_cpu_irqs_sum(), it counts the sum of all software
interrupts on a specified CPU.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 include/linux/kernel_stat.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 90e2fdc17d79ff8..898076e173a928a 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -67,6 +67,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
        return kstat_cpu(cpu).softirqs[irq];
 }
 
+static inline unsigned int kstat_cpu_softirqs_sum(int cpu)
+{
+	int i;
+	unsigned int sum = 0;
+
+	for (i = 0; i < NR_SOFTIRQS; i++)
+		sum += kstat_softirqs_cpu(i, cpu);
+
+	return sum;
+}
+
 /*
  * Number of interrupts per specific IRQ source, since bootup
  */
-- 
2.25.1

Re: [PATCH v7 2/6] sched: Add helper kstat_cpu_softirqs_sum()

[Frederic Weisbecker]

On Fri, Nov 11, 2022 at 09:07:05PM +0800, Zhen Lei wrote:
> Similar to kstat_cpu_irqs_sum(), it counts the sum of all software
> interrupts on a specified CPU.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
>  include/linux/kernel_stat.h | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
> index 90e2fdc17d79ff8..898076e173a928a 100644
> --- a/include/linux/kernel_stat.h
> +++ b/include/linux/kernel_stat.h
> @@ -67,6 +67,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
>         return kstat_cpu(cpu).softirqs[irq];
>  }
>  
> +static inline unsigned int kstat_cpu_softirqs_sum(int cpu)
> +{
> +	int i;
> +	unsigned int sum = 0;
> +
> +	for (i = 0; i < NR_SOFTIRQS; i++)
> +		sum += kstat_softirqs_cpu(i, cpu);

This should return a u64 or at least an unsigned long so that high
numbers of CPUs don't overflow easily.

Thanks.

> +
> +	return sum;
> +}
> +
>  /*
>   * Number of interrupts per specific IRQ source, since bootup
>   */
> -- 
> 2.25.1
> 

Re: [PATCH v7 2/6] sched: Add helper kstat_cpu_softirqs_sum()

[Leizhen (ThunderTown)]

On 2022/11/14 19:42, Frederic Weisbecker wrote:
> On Fri, Nov 11, 2022 at 09:07:05PM +0800, Zhen Lei wrote:
>> Similar to kstat_cpu_irqs_sum(), it counts the sum of all software
>> interrupts on a specified CPU.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>>  include/linux/kernel_stat.h | 11 +++++++++++
>>  1 file changed, 11 insertions(+)
>>
>> diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
>> index 90e2fdc17d79ff8..898076e173a928a 100644
>> --- a/include/linux/kernel_stat.h
>> +++ b/include/linux/kernel_stat.h
>> @@ -67,6 +67,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
>>         return kstat_cpu(cpu).softirqs[irq];
>>  }
>>  
>> +static inline unsigned int kstat_cpu_softirqs_sum(int cpu)
>> +{
>> +	int i;
>> +	unsigned int sum = 0;
>> +
>> +	for (i = 0; i < NR_SOFTIRQS; i++)
>> +		sum += kstat_softirqs_cpu(i, cpu);
> 
> This should return a u64 or at least an unsigned long so that high
> numbers of CPUs don't overflow easily.

OK! Then I'll adjust the following types by the way.

struct kernel_stat {
        unsigned long irqs_sum;
        unsigned int softirqs[NR_SOFTIRQS];
};

static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)




> 
> Thanks.
> 
>> +
>> +	return sum;
>> +}
>> +
>>  /*
>>   * Number of interrupts per specific IRQ source, since bootup
>>   */
>> -- 
>> 2.25.1
>>
> .
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 2/6] sched: Add helper kstat_cpu_softirqs_sum()

[Frederic Weisbecker]

On Mon, Nov 14, 2022 at 08:45:26PM +0800, Leizhen (ThunderTown) wrote:
> 
> 
> On 2022/11/14 19:42, Frederic Weisbecker wrote:
> > On Fri, Nov 11, 2022 at 09:07:05PM +0800, Zhen Lei wrote:
> >> Similar to kstat_cpu_irqs_sum(), it counts the sum of all software
> >> interrupts on a specified CPU.
> >>
> >> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> >> ---
> >>  include/linux/kernel_stat.h | 11 +++++++++++
> >>  1 file changed, 11 insertions(+)
> >>
> >> diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
> >> index 90e2fdc17d79ff8..898076e173a928a 100644
> >> --- a/include/linux/kernel_stat.h
> >> +++ b/include/linux/kernel_stat.h
> >> @@ -67,6 +67,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
> >>         return kstat_cpu(cpu).softirqs[irq];
> >>  }
> >>  
> >> +static inline unsigned int kstat_cpu_softirqs_sum(int cpu)
> >> +{
> >> +	int i;
> >> +	unsigned int sum = 0;
> >> +
> >> +	for (i = 0; i < NR_SOFTIRQS; i++)
> >> +		sum += kstat_softirqs_cpu(i, cpu);
> > 
> > This should return a u64 or at least an unsigned long so that high
> > numbers of CPUs don't overflow easily.
> 
> OK! Then I'll adjust the following types by the way.
> 
> struct kernel_stat {
>         unsigned long irqs_sum;
>         unsigned int softirqs[NR_SOFTIRQS];
> };
> 
> static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)

And I also misread kstat_softirqs_cpu() content, my bad. Although at some point
the sum of all softirqs within a single CPU might overflow in an int so I guess
that still applies...

Thanks.


> 
> 
> 
> 
> > 
> > Thanks.
> > 
> >> +
> >> +	return sum;
> >> +}
> >> +
> >>  /*
> >>   * Number of interrupts per specific IRQ source, since bootup
> >>   */
> >> -- 
> >> 2.25.1
> >>
> > .
> > 
> 
> -- 
> Regards,
>   Zhen Lei

Re: [PATCH v7 2/6] sched: Add helper kstat_cpu_softirqs_sum()

[Leizhen (ThunderTown)]

On 2022/11/14 20:50, Frederic Weisbecker wrote:
> On Mon, Nov 14, 2022 at 08:45:26PM +0800, Leizhen (ThunderTown) wrote:
>>
>>
>> On 2022/11/14 19:42, Frederic Weisbecker wrote:
>>> On Fri, Nov 11, 2022 at 09:07:05PM +0800, Zhen Lei wrote:
>>>> Similar to kstat_cpu_irqs_sum(), it counts the sum of all software
>>>> interrupts on a specified CPU.
>>>>
>>>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>>>> ---
>>>>  include/linux/kernel_stat.h | 11 +++++++++++
>>>>  1 file changed, 11 insertions(+)
>>>>
>>>> diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
>>>> index 90e2fdc17d79ff8..898076e173a928a 100644
>>>> --- a/include/linux/kernel_stat.h
>>>> +++ b/include/linux/kernel_stat.h
>>>> @@ -67,6 +67,17 @@ static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
>>>>         return kstat_cpu(cpu).softirqs[irq];
>>>>  }
>>>>  
>>>> +static inline unsigned int kstat_cpu_softirqs_sum(int cpu)
>>>> +{
>>>> +	int i;
>>>> +	unsigned int sum = 0;
>>>> +
>>>> +	for (i = 0; i < NR_SOFTIRQS; i++)
>>>> +		sum += kstat_softirqs_cpu(i, cpu);
>>>
>>> This should return a u64 or at least an unsigned long so that high
>>> numbers of CPUs don't overflow easily.
>>
>> OK! Then I'll adjust the following types by the way.
>>
>> struct kernel_stat {
>>         unsigned long irqs_sum;
>>         unsigned int softirqs[NR_SOFTIRQS];
>> };
>>
>> static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
> 
> And I also misread kstat_softirqs_cpu() content, my bad. Although at some point
> the sum of all softirqs within a single CPU might overflow in an int so I guess
> that still applies...

Yes, this was discussed before. In fact, I think unsigned int and unsigned
long are all right.

> 
> Thanks.
> 
> 
>>
>>
>>
>>
>>>
>>> Thanks.
>>>
>>>> +
>>>> +	return sum;
>>>> +}
>>>> +
>>>>  /*
>>>>   * Number of interrupts per specific IRQ source, since bootup
>>>>   */
>>>> -- 
>>>> 2.25.1
>>>>
>>> .
>>>
>>
>> -- 
>> Regards,
>>   Zhen Lei
> .
> 

-- 
Regards,
  Zhen Lei

[PATCH v7 3/6] sched: Add helper nr_context_switches_cpu()

[Zhen Lei]

Returns the number of context switches on the specified CPU, which can be
used to diagnose rcu stall.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 include/linux/kernel_stat.h | 1 +
 kernel/sched/core.c         | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 898076e173a928a..9935f7ecbfb9e31 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -52,6 +52,7 @@ DECLARE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
 #define kstat_cpu(cpu) per_cpu(kstat, cpu)
 #define kcpustat_cpu(cpu) per_cpu(kernel_cpustat, cpu)
 
+extern unsigned long long nr_context_switches_cpu(int cpu);
 extern unsigned long long nr_context_switches(void);
 
 extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5800b0623ff3068..a0d19f67f2046d9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5229,6 +5229,11 @@ bool single_task_running(void)
 }
 EXPORT_SYMBOL(single_task_running);
 
+unsigned long long nr_context_switches_cpu(int cpu)
+{
+	return cpu_rq(cpu)->nr_switches;
+}
+
 unsigned long long nr_context_switches(void)
 {
 	int i;
-- 
2.25.1

[PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Zhen Lei]

Because RCU CPU stall warnings are driven from the scheduling-clock
interrupt handler, a workload consisting of a very large number of
short-duration hardware interrupts can result in misleading stall-warning
messages.  On systems supporting only a single level of interrupts,
that is, where interrupts handlers cannot be interrupted, this can
produce misleading diagnostics.  The stack traces will show the
innocent-bystander interrupted task, not the interrupts that are
at the very least exacerbating the stall.

This situation can be improved by displaying the number of interrupts
and the CPU time that they have consumed.  Diagnosing other types
of stalls can be eased by also providing the count of softirqs and
the CPU time that they consumed as well as the number of context
switches and the task-level CPU time consumed.

Consider the following output given this change:

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu:     0-....: (1250 ticks this GP) <omitted>
rcu:          hardirqs   softirqs   csw/system
rcu:  number:      624         45            0
rcu: cputime:       69          1         2425   ==> 2500(ms)

This output shows that the number of hard and soft interrupts is small,
there are no context switches, and the system takes up a lot of time. This
indicates that the current task is looping with preemption disabled.

The impact on system performance is negligible because snapshot is
recorded only once for all continuous RCU stalls.

This added debugging information is suppressed by default and can be
enabled by building the kernel with CONFIG_RCU_CPU_STALL_CPUTIME=y or
by booting with rcupdate.rcu_cpu_stall_cputime=1.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 .../admin-guide/kernel-parameters.txt         |  6 ++++
 kernel/rcu/Kconfig.debug                      | 11 +++++++
 kernel/rcu/rcu.h                              |  1 +
 kernel/rcu/tree.c                             | 18 +++++++++++
 kernel/rcu/tree.h                             | 19 ++++++++++++
 kernel/rcu/tree_stall.h                       | 31 +++++++++++++++++++
 kernel/rcu/update.c                           |  2 ++
 7 files changed, 88 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 811b2e6d4672685..ee7d9d962591c5d 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5084,6 +5084,12 @@
 			rcupdate.rcu_cpu_stall_timeout to be used (after
 			conversion from seconds to milliseconds).
 
+	rcupdate.rcu_cpu_stall_cputime= [KNL]
+			Provide statistics on the cputime and count of
+			interrupts and tasks during the sampling period. For
+			multiple continuous RCU stalls, all sampling periods
+			begin at half of the first RCU stall timeout.
+
 	rcupdate.rcu_expedited= [KNL]
 			Use expedited grace-period primitives, for
 			example, synchronize_rcu_expedited() instead
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 1b0c41d490f0588..025566a9ba44667 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -95,6 +95,17 @@ config RCU_EXP_CPU_STALL_TIMEOUT
 	  says to use the RCU_CPU_STALL_TIMEOUT value converted from
 	  seconds to milliseconds.
 
+config RCU_CPU_STALL_CPUTIME
+	bool "Provide additional RCU stall debug information"
+	depends on RCU_STALL_COMMON
+	default n
+	help
+	  Collect statistics during the sampling period, such as the number of
+	  (hard interrupts, soft interrupts, task switches) and the cputime of
+	  (hard interrupts, soft interrupts, kernel tasks) are added to the
+	  RCU stall report. For multiple continuous RCU stalls, all sampling
+	  periods begin at half of the first RCU stall timeout.
+
 config RCU_TRACE
 	bool "Enable tracing for RCU"
 	depends on DEBUG_KERNEL
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 96122f203187f39..4844dec36bddb48 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -231,6 +231,7 @@ extern int rcu_cpu_stall_ftrace_dump;
 extern int rcu_cpu_stall_suppress;
 extern int rcu_cpu_stall_timeout;
 extern int rcu_exp_cpu_stall_timeout;
+extern int rcu_cpu_stall_cputime;
 int rcu_jiffies_till_stall_check(void);
 int rcu_exp_jiffies_till_stall_check(void);
 
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index ed93ddb8203d42c..3921aacfd421ba9 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -866,6 +866,24 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
 			rdp->rcu_iw_gp_seq = rnp->gp_seq;
 			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
 		}
+
+		if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) {
+			int cpu = rdp->cpu;
+			struct rcu_snap_record *rsrp;
+			struct kernel_cpustat *kcsp;
+
+			kcsp = &kcpustat_cpu(cpu);
+
+			rsrp = &rdp->snap_record;
+			rsrp->cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
+			rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
+			rsrp->cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
+			rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu);
+			rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu);
+			rsrp->nr_csw = nr_context_switches_cpu(rdp->cpu);
+			rsrp->jiffies = jiffies;
+			rsrp->gp_seq = rdp->gp_seq;
+		}
 	}
 
 	return 0;
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index fcb5d696eb1700d..192536916f9a607 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -158,6 +158,23 @@ union rcu_noqs {
 	u16 s; /* Set of bits, aggregate OR here. */
 };
 
+/*
+ * Record the snapshot of the core stats at half of the first RCU stall timeout.
+ * The member gp_seq is used to ensure that all members are updated only once
+ * during the sampling period. The snapshot is taken only if this gp_seq is not
+ * equal to rdp->gp_seq.
+ */
+struct rcu_snap_record {
+	unsigned long	gp_seq;		/* Track rdp->gp_seq counter */
+	u64		cputime_irq;	/* Accumulated cputime of hard irqs */
+	u64		cputime_softirq;/* Accumulated cputime of soft irqs */
+	u64		cputime_system; /* Accumulated cputime of kernel tasks */
+	unsigned long	nr_hardirqs;	/* Accumulated number of hard irqs */
+	unsigned int	nr_softirqs;	/* Accumulated number of soft irqs */
+	unsigned long long nr_csw;	/* Accumulated number of task switches */
+	unsigned long   jiffies;	/* Track jiffies value */
+};
+
 /* Per-CPU data for read-copy update. */
 struct rcu_data {
 	/* 1) quiescent-state and grace-period handling : */
@@ -262,6 +279,8 @@ struct rcu_data {
 	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
 	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
 	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
+	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
+					    /* the first RCU stall timeout */
 
 	long lazy_len;			/* Length of buffered lazy callbacks. */
 	int cpu;
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 5653560573e22d6..a91e844872e59d2 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -428,6 +428,35 @@ static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp
 	return j > 2 * HZ;
 }
 
+static void print_cpu_stat_info(int cpu)
+{
+	struct rcu_snap_record rsr, *rsrp;
+	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
+
+	if (!rcu_cpu_stall_cputime)
+		return;
+
+	rsrp = &rdp->snap_record;
+	if (rsrp->gp_seq != rdp->gp_seq)
+		return;
+
+	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
+	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
+	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
+
+	pr_err("\t         hardirqs   softirqs   csw/system\n");
+	pr_err("\t number: %8ld %10d %12lld\n",
+		kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs,
+		kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs,
+		nr_context_switches_cpu(cpu) - rsrp->nr_csw);
+	pr_err("\tcputime: %8lld %10lld %12lld   ==> %lld(ms)\n",
+		div_u64(rsr.cputime_irq - rsrp->cputime_irq, NSEC_PER_MSEC),
+		div_u64(rsr.cputime_softirq - rsrp->cputime_softirq, NSEC_PER_MSEC),
+		div_u64(rsr.cputime_system - rsrp->cputime_system, NSEC_PER_MSEC),
+		jiffies64_to_msecs(jiffies - rsrp->jiffies));
+}
+
 /*
  * Print out diagnostic information for the specified stalled CPU.
  *
@@ -484,6 +513,8 @@ static void print_cpu_stall_info(int cpu)
 	       data_race(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
 	       rcuc_starved ? buf : "",
 	       falsepositive ? " (false positive?)" : "");
+
+	print_cpu_stat_info(cpu);
 }
 
 /* Complain about starvation of grace-period kthread.  */
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index a05e23648c6b99f..76f9848a21cd5be 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -508,6 +508,8 @@ int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
 module_param(rcu_cpu_stall_timeout, int, 0644);
 int rcu_exp_cpu_stall_timeout __read_mostly = CONFIG_RCU_EXP_CPU_STALL_TIMEOUT;
 module_param(rcu_exp_cpu_stall_timeout, int, 0644);
+int rcu_cpu_stall_cputime __read_mostly = IS_ENABLED(CONFIG_RCU_CPU_STALL_CPUTIME);
+module_param(rcu_cpu_stall_cputime, int, 0644);
 #endif /* #ifdef CONFIG_RCU_STALL_COMMON */
 
 // Suppress boot-time RCU CPU stall warnings and rcutorture writer stall
-- 
2.25.1

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Frederic Weisbecker]

On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
> Because RCU CPU stall warnings are driven from the scheduling-clock
> interrupt handler, a workload consisting of a very large number of
> short-duration hardware interrupts can result in misleading stall-warning
> messages.  On systems supporting only a single level of interrupts,
> that is, where interrupts handlers cannot be interrupted, this can
> produce misleading diagnostics.  The stack traces will show the
> innocent-bystander interrupted task, not the interrupts that are
> at the very least exacerbating the stall.
> 
> This situation can be improved by displaying the number of interrupts
> and the CPU time that they have consumed.  Diagnosing other types
> of stalls can be eased by also providing the count of softirqs and
> the CPU time that they consumed as well as the number of context
> switches and the task-level CPU time consumed.
> 
> Consider the following output given this change:
> 
> rcu: INFO: rcu_preempt self-detected stall on CPU
> rcu:     0-....: (1250 ticks this GP) <omitted>
> rcu:          hardirqs   softirqs   csw/system
> rcu:  number:      624         45            0
> rcu: cputime:       69          1         2425   ==> 2500(ms)
> 
> This output shows that the number of hard and soft interrupts is small,
> there are no context switches, and the system takes up a lot of time. This
> indicates that the current task is looping with preemption disabled.
> 
> The impact on system performance is negligible because snapshot is
> recorded only once for all continuous RCU stalls.
> 
> This added debugging information is suppressed by default and can be
> enabled by building the kernel with CONFIG_RCU_CPU_STALL_CPUTIME=y or
> by booting with rcupdate.rcu_cpu_stall_cputime=1.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> ---
>  .../admin-guide/kernel-parameters.txt         |  6 ++++
>  kernel/rcu/Kconfig.debug                      | 11 +++++++
>  kernel/rcu/rcu.h                              |  1 +
>  kernel/rcu/tree.c                             | 18 +++++++++++
>  kernel/rcu/tree.h                             | 19 ++++++++++++
>  kernel/rcu/tree_stall.h                       | 31 +++++++++++++++++++
>  kernel/rcu/update.c                           |  2 ++
>  7 files changed, 88 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 811b2e6d4672685..ee7d9d962591c5d 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5084,6 +5084,12 @@
>  			rcupdate.rcu_cpu_stall_timeout to be used (after
>  			conversion from seconds to milliseconds).
>  
> +	rcupdate.rcu_cpu_stall_cputime= [KNL]
> +			Provide statistics on the cputime and count of
> +			interrupts and tasks during the sampling period. For
> +			multiple continuous RCU stalls, all sampling periods
> +			begin at half of the first RCU stall timeout.
> +
>  	rcupdate.rcu_expedited= [KNL]
>  			Use expedited grace-period primitives, for
>  			example, synchronize_rcu_expedited() instead
> diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
> index 1b0c41d490f0588..025566a9ba44667 100644
> --- a/kernel/rcu/Kconfig.debug
> +++ b/kernel/rcu/Kconfig.debug
> @@ -95,6 +95,17 @@ config RCU_EXP_CPU_STALL_TIMEOUT
>  	  says to use the RCU_CPU_STALL_TIMEOUT value converted from
>  	  seconds to milliseconds.
>  
> +config RCU_CPU_STALL_CPUTIME
> +	bool "Provide additional RCU stall debug information"
> +	depends on RCU_STALL_COMMON
> +	default n
> +	help
> +	  Collect statistics during the sampling period, such as the number of
> +	  (hard interrupts, soft interrupts, task switches) and the cputime of
> +	  (hard interrupts, soft interrupts, kernel tasks) are added to the
> +	  RCU stall report. For multiple continuous RCU stalls, all sampling
> +	  periods begin at half of the first RCU stall timeout.
> +
>  config RCU_TRACE
>  	bool "Enable tracing for RCU"
>  	depends on DEBUG_KERNEL
> diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
> index 96122f203187f39..4844dec36bddb48 100644
> --- a/kernel/rcu/rcu.h
> +++ b/kernel/rcu/rcu.h
> @@ -231,6 +231,7 @@ extern int rcu_cpu_stall_ftrace_dump;
>  extern int rcu_cpu_stall_suppress;
>  extern int rcu_cpu_stall_timeout;
>  extern int rcu_exp_cpu_stall_timeout;
> +extern int rcu_cpu_stall_cputime;
>  int rcu_jiffies_till_stall_check(void);
>  int rcu_exp_jiffies_till_stall_check(void);
>  
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index ed93ddb8203d42c..3921aacfd421ba9 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -866,6 +866,24 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
>  			rdp->rcu_iw_gp_seq = rnp->gp_seq;
>  			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
>  		}
> +
> +		if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) {
> +			int cpu = rdp->cpu;
> +			struct rcu_snap_record *rsrp;
> +			struct kernel_cpustat *kcsp;
> +
> +			kcsp = &kcpustat_cpu(cpu);
> +
> +			rsrp = &rdp->snap_record;
> +			rsrp->cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
> +			rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
> +			rsrp->cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
> +			rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu);
> +			rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu);

Getting the sum of all CPU's IRQs, with even two iterations on all of them, look
costly. So I have to ask: why is this information useful and why can't we deduce
it from other CPUs stall reports?

I'm also asking because this rcu_cpu_stall_cputime is likely to be very useful for
distros, to the point that I expect it to be turned on by default as doing a
snapshot of kcpustat fields is cheap. But doing that wide CPU snapshot is
definetly going to be an unbearable overhead.

Thanks.

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Leizhen (ThunderTown)]

On 2022/11/14 19:24, Frederic Weisbecker wrote:
> On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
>> Because RCU CPU stall warnings are driven from the scheduling-clock
>> interrupt handler, a workload consisting of a very large number of
>> short-duration hardware interrupts can result in misleading stall-warning
>> messages.  On systems supporting only a single level of interrupts,
>> that is, where interrupts handlers cannot be interrupted, this can
>> produce misleading diagnostics.  The stack traces will show the
>> innocent-bystander interrupted task, not the interrupts that are
>> at the very least exacerbating the stall.
>>
>> This situation can be improved by displaying the number of interrupts
>> and the CPU time that they have consumed.  Diagnosing other types
>> of stalls can be eased by also providing the count of softirqs and
>> the CPU time that they consumed as well as the number of context
>> switches and the task-level CPU time consumed.
>>
>> Consider the following output given this change:
>>
>> rcu: INFO: rcu_preempt self-detected stall on CPU
>> rcu:     0-....: (1250 ticks this GP) <omitted>
>> rcu:          hardirqs   softirqs   csw/system
>> rcu:  number:      624         45            0
>> rcu: cputime:       69          1         2425   ==> 2500(ms)
>>
>> This output shows that the number of hard and soft interrupts is small,
>> there are no context switches, and the system takes up a lot of time. This
>> indicates that the current task is looping with preemption disabled.
>>
>> The impact on system performance is negligible because snapshot is
>> recorded only once for all continuous RCU stalls.
>>
>> This added debugging information is suppressed by default and can be
>> enabled by building the kernel with CONFIG_RCU_CPU_STALL_CPUTIME=y or
>> by booting with rcupdate.rcu_cpu_stall_cputime=1.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
>> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
>> ---
>>  .../admin-guide/kernel-parameters.txt         |  6 ++++
>>  kernel/rcu/Kconfig.debug                      | 11 +++++++
>>  kernel/rcu/rcu.h                              |  1 +
>>  kernel/rcu/tree.c                             | 18 +++++++++++
>>  kernel/rcu/tree.h                             | 19 ++++++++++++
>>  kernel/rcu/tree_stall.h                       | 31 +++++++++++++++++++
>>  kernel/rcu/update.c                           |  2 ++
>>  7 files changed, 88 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>> index 811b2e6d4672685..ee7d9d962591c5d 100644
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -5084,6 +5084,12 @@
>>  			rcupdate.rcu_cpu_stall_timeout to be used (after
>>  			conversion from seconds to milliseconds).
>>  
>> +	rcupdate.rcu_cpu_stall_cputime= [KNL]
>> +			Provide statistics on the cputime and count of
>> +			interrupts and tasks during the sampling period. For
>> +			multiple continuous RCU stalls, all sampling periods
>> +			begin at half of the first RCU stall timeout.
>> +
>>  	rcupdate.rcu_expedited= [KNL]
>>  			Use expedited grace-period primitives, for
>>  			example, synchronize_rcu_expedited() instead
>> diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
>> index 1b0c41d490f0588..025566a9ba44667 100644
>> --- a/kernel/rcu/Kconfig.debug
>> +++ b/kernel/rcu/Kconfig.debug
>> @@ -95,6 +95,17 @@ config RCU_EXP_CPU_STALL_TIMEOUT
>>  	  says to use the RCU_CPU_STALL_TIMEOUT value converted from
>>  	  seconds to milliseconds.
>>  
>> +config RCU_CPU_STALL_CPUTIME
>> +	bool "Provide additional RCU stall debug information"
>> +	depends on RCU_STALL_COMMON
>> +	default n
>> +	help
>> +	  Collect statistics during the sampling period, such as the number of
>> +	  (hard interrupts, soft interrupts, task switches) and the cputime of
>> +	  (hard interrupts, soft interrupts, kernel tasks) are added to the
>> +	  RCU stall report. For multiple continuous RCU stalls, all sampling
>> +	  periods begin at half of the first RCU stall timeout.
>> +
>>  config RCU_TRACE
>>  	bool "Enable tracing for RCU"
>>  	depends on DEBUG_KERNEL
>> diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
>> index 96122f203187f39..4844dec36bddb48 100644
>> --- a/kernel/rcu/rcu.h
>> +++ b/kernel/rcu/rcu.h
>> @@ -231,6 +231,7 @@ extern int rcu_cpu_stall_ftrace_dump;
>>  extern int rcu_cpu_stall_suppress;
>>  extern int rcu_cpu_stall_timeout;
>>  extern int rcu_exp_cpu_stall_timeout;
>> +extern int rcu_cpu_stall_cputime;
>>  int rcu_jiffies_till_stall_check(void);
>>  int rcu_exp_jiffies_till_stall_check(void);
>>  
>> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> index ed93ddb8203d42c..3921aacfd421ba9 100644
>> --- a/kernel/rcu/tree.c
>> +++ b/kernel/rcu/tree.c
>> @@ -866,6 +866,24 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
>>  			rdp->rcu_iw_gp_seq = rnp->gp_seq;
>>  			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
>>  		}
>> +
>> +		if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) {
>> +			int cpu = rdp->cpu;
>> +			struct rcu_snap_record *rsrp;
>> +			struct kernel_cpustat *kcsp;
>> +
>> +			kcsp = &kcpustat_cpu(cpu);
>> +
>> +			rsrp = &rdp->snap_record;
>> +			rsrp->cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
>> +			rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
>> +			rsrp->cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
>> +			rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu);
>> +			rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu);
> 
> Getting the sum of all CPU's IRQs, with even two iterations on all of them, look
> costly. So I have to ask: why is this information useful and why can't we deduce
> it from other CPUs stall reports?

Only the RCU stalled CPUs are recorded. Why all CPUs?

static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
{
	rcu_for_each_leaf_node(rnp) {
		if (rnp->qsmask == 0) {
			continue;
		}
		for_each_leaf_node_cpu_mask(rnp, cpu, rnp->qsmask) {
			if (f(rdp))

> 
> I'm also asking because this rcu_cpu_stall_cputime is likely to be very useful for
> distros, to the point that I expect it to be turned on by default as doing a
> snapshot of kcpustat fields is cheap. But doing that wide CPU snapshot is
> definetly going to be an unbearable overhead.

I purposely added a print test, only the RCU stalled CPU would be taken snapshots and
calculated differentials.

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index d1f0d857dc85df5..693e7c83bd17d1e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -872,6 +872,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
                        struct rcu_snap_record *rsrp;
                        struct kernel_cpustat *kcsp;

+                       printk("fixme: cpu=%d\n", smp_processor_id());
                        kcsp = &kcpustat_cpu(cpu);

                        rsrp = &rdp->snap_record;

> 
> Thanks.
> .
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Frederic Weisbecker]

On Mon, Nov 14, 2022 at 08:32:19PM +0800, Leizhen (ThunderTown) wrote:
> >> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> >> index ed93ddb8203d42c..3921aacfd421ba9 100644
> >> --- a/kernel/rcu/tree.c
> >> +++ b/kernel/rcu/tree.c
> >> @@ -866,6 +866,24 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp)
> >>  			rdp->rcu_iw_gp_seq = rnp->gp_seq;
> >>  			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
> >>  		}
> >> +
> >> +		if (rcu_cpu_stall_cputime && rdp->snap_record.gp_seq != rdp->gp_seq) {
> >> +			int cpu = rdp->cpu;
> >> +			struct rcu_snap_record *rsrp;
> >> +			struct kernel_cpustat *kcsp;
> >> +
> >> +			kcsp = &kcpustat_cpu(cpu);
> >> +
> >> +			rsrp = &rdp->snap_record;
> >> +			rsrp->cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
> >> +			rsrp->cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
> >> +			rsrp->cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
> >> +			rsrp->nr_hardirqs = kstat_cpu_irqs_sum(rdp->cpu);
> >> +			rsrp->nr_softirqs = kstat_cpu_softirqs_sum(rdp->cpu);
> > 
> > Getting the sum of all CPU's IRQs, with even two iterations on all of them, look
> > costly. So I have to ask: why is this information useful and why can't we deduce
> > it from other CPUs stall reports?
> 
> Only the RCU stalled CPUs are recorded. Why all CPUs?

Bah, I misread kstat_cpu_softirqs_sum() kstat_cpu_irqs_sum() content. Sorry
about that, my brainfart... :-)

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Frederic Weisbecker]

On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
> @@ -262,6 +279,8 @@ struct rcu_data {
>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
> +					    /* the first RCU stall timeout */

This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME

> +static void print_cpu_stat_info(int cpu)
> +{
> +	struct rcu_snap_record rsr, *rsrp;
> +	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
> +	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
> +
> +	if (!rcu_cpu_stall_cputime)
> +		return;
> +
> +	rsrp = &rdp->snap_record;
> +	if (rsrp->gp_seq != rdp->gp_seq)
> +		return;
> +
> +	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
> +	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
> +	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
> +
> +	pr_err("\t         hardirqs   softirqs   csw/system\n");
> +	pr_err("\t number: %8ld %10d %12lld\n",
> +		kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs,
> +		kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs,
> +		nr_context_switches_cpu(cpu) - rsrp->nr_csw);
> +	pr_err("\tcputime: %8lld %10lld %12lld   ==> %lld(ms)\n",
> +		div_u64(rsr.cputime_irq - rsrp->cputime_irq, NSEC_PER_MSEC),
> +		div_u64(rsr.cputime_softirq - rsrp->cputime_softirq, NSEC_PER_MSEC),
> +		div_u64(rsr.cputime_system - rsrp->cputime_system, NSEC_PER_MSEC),
> +		jiffies64_to_msecs(jiffies - rsrp->jiffies));

jiffies_to_msecs() should be enough.

Thanks.

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Leizhen (ThunderTown)]

On 2022/11/17 6:39, Frederic Weisbecker wrote:
> On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
>> @@ -262,6 +279,8 @@ struct rcu_data {
>>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
>>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
>>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
>> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
>> +					    /* the first RCU stall timeout */
> 
> This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME

This will not work for now because we also support boot option rcupdate.rcu_cpu_stall_cputime.

> 
>> +static void print_cpu_stat_info(int cpu)
>> +{
>> +	struct rcu_snap_record rsr, *rsrp;
>> +	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
>> +	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
>> +
>> +	if (!rcu_cpu_stall_cputime)
>> +		return;
>> +
>> +	rsrp = &rdp->snap_record;
>> +	if (rsrp->gp_seq != rdp->gp_seq)
>> +		return;
>> +
>> +	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
>> +	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
>> +	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
>> +
>> +	pr_err("\t         hardirqs   softirqs   csw/system\n");
>> +	pr_err("\t number: %8ld %10d %12lld\n",
>> +		kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs,
>> +		kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs,
>> +		nr_context_switches_cpu(cpu) - rsrp->nr_csw);
>> +	pr_err("\tcputime: %8lld %10lld %12lld   ==> %lld(ms)\n",
>> +		div_u64(rsr.cputime_irq - rsrp->cputime_irq, NSEC_PER_MSEC),
>> +		div_u64(rsr.cputime_softirq - rsrp->cputime_softirq, NSEC_PER_MSEC),
>> +		div_u64(rsr.cputime_system - rsrp->cputime_system, NSEC_PER_MSEC),
>> +		jiffies64_to_msecs(jiffies - rsrp->jiffies));
> 
> jiffies_to_msecs() should be enough.

OK, thanks.

> 
> Thanks.
> 
> .
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Frederic Weisbecker]

On Thu, Nov 17, 2022 at 09:57:18AM +0800, Leizhen (ThunderTown) wrote:
> 
> 
> On 2022/11/17 6:39, Frederic Weisbecker wrote:
> > On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
> >> @@ -262,6 +279,8 @@ struct rcu_data {
> >>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
> >>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
> >>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
> >> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
> >> +					    /* the first RCU stall timeout */
> > 
> > This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME
> 
> This will not work for now because we also support boot option
> rcupdate.rcu_cpu_stall_cputime.

I'm confused. If CONFIG_RCU_CPU_STALL_CPUTIME=n then rcupdate.rcu_cpu_stall_cputime has
no effect, right?

Thanks.

> 
> > 
> >> +static void print_cpu_stat_info(int cpu)
> >> +{
> >> +	struct rcu_snap_record rsr, *rsrp;
> >> +	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
> >> +	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
> >> +
> >> +	if (!rcu_cpu_stall_cputime)
> >> +		return;
> >> +
> >> +	rsrp = &rdp->snap_record;
> >> +	if (rsrp->gp_seq != rdp->gp_seq)
> >> +		return;
> >> +
> >> +	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
> >> +	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
> >> +	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
> >> +
> >> +	pr_err("\t         hardirqs   softirqs   csw/system\n");
> >> +	pr_err("\t number: %8ld %10d %12lld\n",
> >> +		kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs,
> >> +		kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs,
> >> +		nr_context_switches_cpu(cpu) - rsrp->nr_csw);
> >> +	pr_err("\tcputime: %8lld %10lld %12lld   ==> %lld(ms)\n",
> >> +		div_u64(rsr.cputime_irq - rsrp->cputime_irq, NSEC_PER_MSEC),
> >> +		div_u64(rsr.cputime_softirq - rsrp->cputime_softirq, NSEC_PER_MSEC),
> >> +		div_u64(rsr.cputime_system - rsrp->cputime_system, NSEC_PER_MSEC),
> >> +		jiffies64_to_msecs(jiffies - rsrp->jiffies));
> > 
> > jiffies_to_msecs() should be enough.
> 
> OK, thanks.
> 
> > 
> > Thanks.
> > 
> > .
> > 
> 
> -- 
> Regards,
>   Zhen Lei

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Leizhen (ThunderTown)]

On 2022/11/17 20:22, Frederic Weisbecker wrote:
> On Thu, Nov 17, 2022 at 09:57:18AM +0800, Leizhen (ThunderTown) wrote:
>>
>>
>> On 2022/11/17 6:39, Frederic Weisbecker wrote:
>>> On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
>>>> @@ -262,6 +279,8 @@ struct rcu_data {
>>>>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
>>>>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
>>>>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
>>>> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
>>>> +					    /* the first RCU stall timeout */
>>>
>>> This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME
>>
>> This will not work for now because we also support boot option
>> rcupdate.rcu_cpu_stall_cputime.
> 
> I'm confused. If CONFIG_RCU_CPU_STALL_CPUTIME=n then rcupdate.rcu_cpu_stall_cputime has
> no effect, right?

No, rcupdate.rcu_cpu_stall_cputime override CONFIG_RCU_CPU_STALL_CPUTIME. Because
the default value of CONFIG_RCU_CPU_STALL_CPUTIME is n, so in most cases, we need
rcupdate.rcu_cpu_stall_cputime as the escape route.

If CONFIG_RCU_CPU_STALL_CPUTIME=y is default, your suggestion is more appropriate.

> 
> Thanks.
> 
>>
>>>
>>>> +static void print_cpu_stat_info(int cpu)
>>>> +{
>>>> +	struct rcu_snap_record rsr, *rsrp;
>>>> +	struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
>>>> +	struct kernel_cpustat *kcsp = &kcpustat_cpu(cpu);
>>>> +
>>>> +	if (!rcu_cpu_stall_cputime)
>>>> +		return;
>>>> +
>>>> +	rsrp = &rdp->snap_record;
>>>> +	if (rsrp->gp_seq != rdp->gp_seq)
>>>> +		return;
>>>> +
>>>> +	rsr.cputime_irq     = kcpustat_field(kcsp, CPUTIME_IRQ, cpu);
>>>> +	rsr.cputime_softirq = kcpustat_field(kcsp, CPUTIME_SOFTIRQ, cpu);
>>>> +	rsr.cputime_system  = kcpustat_field(kcsp, CPUTIME_SYSTEM, cpu);
>>>> +
>>>> +	pr_err("\t         hardirqs   softirqs   csw/system\n");
>>>> +	pr_err("\t number: %8ld %10d %12lld\n",
>>>> +		kstat_cpu_irqs_sum(cpu) - rsrp->nr_hardirqs,
>>>> +		kstat_cpu_softirqs_sum(cpu) - rsrp->nr_softirqs,
>>>> +		nr_context_switches_cpu(cpu) - rsrp->nr_csw);
>>>> +	pr_err("\tcputime: %8lld %10lld %12lld   ==> %lld(ms)\n",
>>>> +		div_u64(rsr.cputime_irq - rsrp->cputime_irq, NSEC_PER_MSEC),
>>>> +		div_u64(rsr.cputime_softirq - rsrp->cputime_softirq, NSEC_PER_MSEC),
>>>> +		div_u64(rsr.cputime_system - rsrp->cputime_system, NSEC_PER_MSEC),
>>>> +		jiffies64_to_msecs(jiffies - rsrp->jiffies));
>>>
>>> jiffies_to_msecs() should be enough.
>>
>> OK, thanks.
>>
>>>
>>> Thanks.
>>>
>>> .
>>>
>>
>> -- 
>> Regards,
>>   Zhen Lei
> .
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Frederic Weisbecker]

On Thu, Nov 17, 2022 at 09:25:44PM +0800, Leizhen (ThunderTown) wrote:
> 
> 
> On 2022/11/17 20:22, Frederic Weisbecker wrote:
> > On Thu, Nov 17, 2022 at 09:57:18AM +0800, Leizhen (ThunderTown) wrote:
> >>
> >>
> >> On 2022/11/17 6:39, Frederic Weisbecker wrote:
> >>> On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
> >>>> @@ -262,6 +279,8 @@ struct rcu_data {
> >>>>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
> >>>>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
> >>>>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
> >>>> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
> >>>> +					    /* the first RCU stall timeout */
> >>>
> >>> This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME
> >>
> >> This will not work for now because we also support boot option
> >> rcupdate.rcu_cpu_stall_cputime.
> > 
> > I'm confused. If CONFIG_RCU_CPU_STALL_CPUTIME=n then rcupdate.rcu_cpu_stall_cputime has
> > no effect, right?
> 
> No, rcupdate.rcu_cpu_stall_cputime override CONFIG_RCU_CPU_STALL_CPUTIME. Because
> the default value of CONFIG_RCU_CPU_STALL_CPUTIME is n, so in most cases, we need
> rcupdate.rcu_cpu_stall_cputime as the escape route.
> 
> If CONFIG_RCU_CPU_STALL_CPUTIME=y is default, your suggestion is more
> appropriate.

Oh ok I thought it was a support Kconfig switch.

Then please just mention that rcupdate.rcu_cpu_stall_cputime overrides
CONFIG_RCU_CPU_STALL_CPUTIME behaviour in the Kconfig help text.

Thanks.

Re: [PATCH v7 4/6] rcu: Add RCU stall diagnosis information

[Leizhen (ThunderTown)]

On 2022/11/17 22:26, Frederic Weisbecker wrote:
> On Thu, Nov 17, 2022 at 09:25:44PM +0800, Leizhen (ThunderTown) wrote:
>>
>>
>> On 2022/11/17 20:22, Frederic Weisbecker wrote:
>>> On Thu, Nov 17, 2022 at 09:57:18AM +0800, Leizhen (ThunderTown) wrote:
>>>>
>>>>
>>>> On 2022/11/17 6:39, Frederic Weisbecker wrote:
>>>>> On Fri, Nov 11, 2022 at 09:07:07PM +0800, Zhen Lei wrote:
>>>>>> @@ -262,6 +279,8 @@ struct rcu_data {
>>>>>>  	short rcu_onl_gp_flags;		/* ->gp_flags at last online. */
>>>>>>  	unsigned long last_fqs_resched;	/* Time of last rcu_resched(). */
>>>>>>  	unsigned long last_sched_clock;	/* Jiffies of last rcu_sched_clock_irq(). */
>>>>>> +	struct rcu_snap_record snap_record; /* Snapshot of core stats at half of */
>>>>>> +					    /* the first RCU stall timeout */
>>>>>
>>>>> This should be under #ifdef CONFIG_RCU_CPU_STALL_CPUTIME
>>>>
>>>> This will not work for now because we also support boot option
>>>> rcupdate.rcu_cpu_stall_cputime.
>>>
>>> I'm confused. If CONFIG_RCU_CPU_STALL_CPUTIME=n then rcupdate.rcu_cpu_stall_cputime has
>>> no effect, right?
>>
>> No, rcupdate.rcu_cpu_stall_cputime override CONFIG_RCU_CPU_STALL_CPUTIME. Because
>> the default value of CONFIG_RCU_CPU_STALL_CPUTIME is n, so in most cases, we need
>> rcupdate.rcu_cpu_stall_cputime as the escape route.
>>
>> If CONFIG_RCU_CPU_STALL_CPUTIME=y is default, your suggestion is more
>> appropriate.
> 
> Oh ok I thought it was a support Kconfig switch.
> 
> Then please just mention that rcupdate.rcu_cpu_stall_cputime overrides
> CONFIG_RCU_CPU_STALL_CPUTIME behaviour in the Kconfig help text.

Okay, I'll add the description.

> 
> Thanks.
> .
> 

-- 
Regards,
  Zhen Lei

[PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[Zhen Lei]

This commit doucments how to quickly determine the bug causing a given
RCU CPU stall fault warning based on the output information provided
by CONFIG_RCU_CPU_STALL_CPUTIME=y.

[ paulmck: Apply wordsmithing. ]

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 Documentation/RCU/stallwarn.rst | 88 +++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
index dfa4db8c0931eaf..5e24e849290a286 100644
--- a/Documentation/RCU/stallwarn.rst
+++ b/Documentation/RCU/stallwarn.rst
@@ -390,3 +390,91 @@ for example, "P3421".
 
 It is entirely possible to see stall warnings from normal and from
 expedited grace periods at about the same time during the same run.
+
+RCU_CPU_STALL_CPUTIME
+=====================
+
+In kernels built with CONFIG_RCU_CPU_STALL_CPUTIME=y or booted with
+rcupdate.rcu_cpu_stall_cputime=1, the following additional information
+is supplied with each RCU CPU stall warning::
+
+rcu:          hardirqs   softirqs   csw/system
+rcu:  number:      624         45            0
+rcu: cputime:       69          1         2425   ==> 2500(ms)
+
+These statistics are collected during the sampling period. The values
+in row "number:" are the number of hard interrupts, number of soft
+interrupts, and number of context switches on the stalled CPU. The
+first three values in row "cputime:" indicate the CPU time in
+milliseconds consumed by hard interrupts, soft interrupts, and tasks
+on the stalled CPU.  The last number is the measurement interval, again
+in milliseconds.  Because user-mode tasks normally do not cause RCU CPU
+stalls, these tasks are typically kernel tasks, which is why only the
+system CPU time are considered.
+
+The sampling period is shown as follows:
+|<------------first timeout---------->|<-----second timeout----->|
+|<--half timeout-->|<--half timeout-->|                          |
+|                  |<--first period-->|                          |
+|                  |<-----------second sampling period---------->|
+|                  |                  |                          |
+|          sampling time point    1st-stall                  2nd-stall
+
+
+The following describes four typical scenarios:
+
+1. A CPU looping with interrupts disabled.::
+
+   rcu:          hardirqs   softirqs   csw/system
+   rcu:  number:        0          0            0
+   rcu: cputime:        0          0            0   ==> 2500(ms)
+
+   Because interrupts have been disabled throughout the measurement
+   interval, there are no interrupts and no context switches.
+   Furthermore, because CPU time consumption was measured using interrupt
+   handlers, the system CPU consumption is misleadingly measured as zero.
+   This scenario will normally also have "(0 ticks this GP)" printed on
+   this CPU's summary line.
+
+2. A CPU looping with bottom halves disabled.
+
+   This is similar to the previous example, but with non-zero number of
+   and CPU time consumed by hard interrupts, along with non-zero CPU
+   time consumed by in-kernel execution.::
+
+   rcu:          hardirqs   softirqs   csw/system
+   rcu:  number:      624          0            0
+   rcu: cputime:       49          0         2446   ==> 2500(ms)
+
+   The fact that there are zero softirqs gives a hint that these were
+   disabled, perhaps via local_bh_disable().  It is of course possible
+   that there were no softirqs, perhaps because all events that would
+   result in softirq execution are confined to other CPUs.  In this case,
+   the diagnosis should continue as shown in the next example.
+
+3. A CPU looping with preemption disabled.
+
+   Here, only the number of context switches is zero.::
+
+   rcu:          hardirqs   softirqs   csw/system
+   rcu:  number:      624         45            0
+   rcu: cputime:       69          1         2425   ==> 2500(ms)
+
+   This situation hints that the stalled CPU was looping with preemption
+   disabled.
+
+4. No looping, but massive hard and soft interrupts.::
+
+   rcu:          hardirqs   softirqs   csw/system
+   rcu:  number:       xx         xx            0
+   rcu: cputime:       xx         xx            0   ==> 2500(ms)
+
+   Here, the number and CPU time of hard interrupts are all non-zero,
+   but the number of context switches and the in-kernel CPU time consumed
+   are zero. The number and cputime of soft interrupts will usually be
+   non-zero, but could be zero, for example, if the CPU was spinning
+   within a single hard interrupt handler.
+
+   If this type of RCU CPU stall warning can be reproduced, you can
+   narrow it down by looking at /proc/interrupts or by writing code to
+   trace each interrupt, for example, by referring to show_interrupts().
-- 
2.25.1

Re: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 2564 bytes --]

Hi Zhen,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on paulmck-rcu/dev]
[also build test WARNING on tip/sched/core linus/master v6.1-rc4 next-20221111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Zhen-Lei/rcu-Add-RCU-stall-diagnosis-information/20221111-211035
base:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
patch link:    https://lore.kernel.org/r/20221111130709.247-6-thunder.leizhen%40huawei.com
patch subject: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information
reproduce:
        # https://github.com/intel-lab-lkp/linux/commit/062a824ff2c71185d19ff8d39fef18fda82e474f
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Zhen-Lei/rcu-Add-RCU-stall-diagnosis-information/20221111-211035
        git checkout 062a824ff2c71185d19ff8d39fef18fda82e474f
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        make htmldocs

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<------------first timeout---------->|<-----second timeout----->".
>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<--half timeout-->|<--half timeout-->".
>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<--first period-->".
>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<-----------second sampling period---------->".

vim +415 Documentation/RCU/stallwarn.rst

   414	
 > 415	The sampling period is shown as follows:
   416	|<------------first timeout---------->|<-----second timeout----->|
   417	|<--half timeout-->|<--half timeout-->|                          |
   418	|                  |<--first period-->|                          |
   419	|                  |<-----------second sampling period---------->|
   420	|                  |                  |                          |
   421	|          sampling time point    1st-stall                  2nd-stall
   422	
   423	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

[-- Attachment #2: config --]
[-- Type: text/plain, Size: 38909 bytes --]

#
# Automatically generated file; DO NOT EDIT.
# Linux/x86_64 6.1.0-rc1 Kernel Configuration
#
CONFIG_CC_VERSION_TEXT="gcc-11 (Debian 11.3.0-8) 11.3.0"
CONFIG_CC_IS_GCC=y
CONFIG_GCC_VERSION=110300
CONFIG_CLANG_VERSION=0
CONFIG_AS_IS_GNU=y
CONFIG_AS_VERSION=23900
CONFIG_LD_IS_BFD=y
CONFIG_LD_VERSION=23900
CONFIG_LLD_VERSION=0
CONFIG_CC_CAN_LINK=y
CONFIG_CC_CAN_LINK_STATIC=y
CONFIG_CC_HAS_ASM_GOTO_OUTPUT=y
CONFIG_CC_HAS_ASM_INLINE=y
CONFIG_CC_HAS_NO_PROFILE_FN_ATTR=y
CONFIG_PAHOLE_VERSION=123
CONFIG_IRQ_WORK=y
CONFIG_BUILDTIME_TABLE_SORT=y
CONFIG_THREAD_INFO_IN_TASK=y

#
# General setup
#
CONFIG_BROKEN_ON_SMP=y
CONFIG_INIT_ENV_ARG_LIMIT=32
CONFIG_COMPILE_TEST=y
# CONFIG_WERROR is not set
CONFIG_LOCALVERSION=""
CONFIG_BUILD_SALT=""
CONFIG_HAVE_KERNEL_GZIP=y
CONFIG_HAVE_KERNEL_BZIP2=y
CONFIG_HAVE_KERNEL_LZMA=y
CONFIG_HAVE_KERNEL_XZ=y
CONFIG_HAVE_KERNEL_LZO=y
CONFIG_HAVE_KERNEL_LZ4=y
CONFIG_HAVE_KERNEL_ZSTD=y
CONFIG_KERNEL_GZIP=y
# CONFIG_KERNEL_BZIP2 is not set
# CONFIG_KERNEL_LZMA is not set
# CONFIG_KERNEL_XZ is not set
# CONFIG_KERNEL_LZO is not set
# CONFIG_KERNEL_LZ4 is not set
# CONFIG_KERNEL_ZSTD is not set
CONFIG_DEFAULT_INIT=""
CONFIG_DEFAULT_HOSTNAME="(none)"
# CONFIG_SYSVIPC is not set
# CONFIG_WATCH_QUEUE is not set
# CONFIG_CROSS_MEMORY_ATTACH is not set
# CONFIG_USELIB is not set
CONFIG_HAVE_ARCH_AUDITSYSCALL=y

#
# IRQ subsystem
#
CONFIG_GENERIC_IRQ_PROBE=y
CONFIG_GENERIC_IRQ_SHOW=y
CONFIG_HARDIRQS_SW_RESEND=y
CONFIG_IRQ_DOMAIN=y
CONFIG_IRQ_DOMAIN_HIERARCHY=y
CONFIG_GENERIC_IRQ_MATRIX_ALLOCATOR=y
CONFIG_GENERIC_IRQ_RESERVATION_MODE=y
CONFIG_IRQ_FORCED_THREADING=y
CONFIG_SPARSE_IRQ=y
# end of IRQ subsystem

CONFIG_CLOCKSOURCE_WATCHDOG=y
CONFIG_ARCH_CLOCKSOURCE_INIT=y
CONFIG_CLOCKSOURCE_VALIDATE_LAST_CYCLE=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST=y
CONFIG_GENERIC_CMOS_UPDATE=y
CONFIG_HAVE_POSIX_CPU_TIMERS_TASK_WORK=y
CONFIG_POSIX_CPU_TIMERS_TASK_WORK=y

#
# Timers subsystem
#
CONFIG_HZ_PERIODIC=y
# CONFIG_NO_HZ_IDLE is not set
# CONFIG_NO_HZ is not set
# CONFIG_HIGH_RES_TIMERS is not set
CONFIG_CLOCKSOURCE_WATCHDOG_MAX_SKEW_US=100
# end of Timers subsystem

CONFIG_HAVE_EBPF_JIT=y
CONFIG_ARCH_WANT_DEFAULT_BPF_JIT=y

#
# BPF subsystem
#
# CONFIG_BPF_SYSCALL is not set
# end of BPF subsystem

CONFIG_PREEMPT_NONE_BUILD=y
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
# CONFIG_PREEMPT_DYNAMIC is not set

#
# CPU/Task time and stats accounting
#
CONFIG_TICK_CPU_ACCOUNTING=y
# CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set
# CONFIG_IRQ_TIME_ACCOUNTING is not set
# CONFIG_BSD_PROCESS_ACCT is not set
# CONFIG_PSI is not set
# end of CPU/Task time and stats accounting

CONFIG_CPU_ISOLATION=y

#
# RCU Subsystem
#
CONFIG_TINY_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_SRCU=y
CONFIG_TINY_SRCU=y
# end of RCU Subsystem

# CONFIG_IKCONFIG is not set
# CONFIG_IKHEADERS is not set
CONFIG_LOG_BUF_SHIFT=17
CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT=13
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y

#
# Scheduler features
#
# end of Scheduler features

CONFIG_ARCH_SUPPORTS_NUMA_BALANCING=y
CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH=y
CONFIG_CC_HAS_INT128=y
CONFIG_CC_IMPLICIT_FALLTHROUGH="-Wimplicit-fallthrough=5"
CONFIG_GCC12_NO_ARRAY_BOUNDS=y
CONFIG_ARCH_SUPPORTS_INT128=y
# CONFIG_CGROUPS is not set
CONFIG_NAMESPACES=y
# CONFIG_UTS_NS is not set
# CONFIG_TIME_NS is not set
# CONFIG_USER_NS is not set
# CONFIG_PID_NS is not set
# CONFIG_CHECKPOINT_RESTORE is not set
# CONFIG_SCHED_AUTOGROUP is not set
# CONFIG_SYSFS_DEPRECATED is not set
# CONFIG_RELAY is not set
# CONFIG_BLK_DEV_INITRD is not set
# CONFIG_BOOT_CONFIG is not set
# CONFIG_INITRAMFS_PRESERVE_MTIME is not set
CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE=y
# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_LD_ORPHAN_WARN=y
CONFIG_SYSCTL=y
CONFIG_SYSCTL_EXCEPTION_TRACE=y
CONFIG_HAVE_PCSPKR_PLATFORM=y
# CONFIG_EXPERT is not set
CONFIG_MULTIUSER=y
CONFIG_SGETMASK_SYSCALL=y
CONFIG_SYSFS_SYSCALL=y
CONFIG_FHANDLE=y
CONFIG_POSIX_TIMERS=y
CONFIG_PRINTK=y
CONFIG_BUG=y
CONFIG_ELF_CORE=y
CONFIG_PCSPKR_PLATFORM=y
CONFIG_BASE_FULL=y
CONFIG_FUTEX=y
CONFIG_FUTEX_PI=y
CONFIG_EPOLL=y
CONFIG_SIGNALFD=y
CONFIG_TIMERFD=y
CONFIG_EVENTFD=y
CONFIG_SHMEM=y
CONFIG_AIO=y
CONFIG_IO_URING=y
CONFIG_ADVISE_SYSCALLS=y
CONFIG_MEMBARRIER=y
CONFIG_KALLSYMS=y
CONFIG_KALLSYMS_BASE_RELATIVE=y
CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE=y
CONFIG_RSEQ=y
# CONFIG_EMBEDDED is not set
CONFIG_HAVE_PERF_EVENTS=y

#
# Kernel Performance Events And Counters
#
CONFIG_PERF_EVENTS=y
# end of Kernel Performance Events And Counters

# CONFIG_PROFILING is not set
# end of General setup

CONFIG_64BIT=y
CONFIG_X86_64=y
CONFIG_X86=y
CONFIG_INSTRUCTION_DECODER=y
CONFIG_OUTPUT_FORMAT="elf64-x86-64"
CONFIG_LOCKDEP_SUPPORT=y
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_MMU=y
CONFIG_ARCH_MMAP_RND_BITS_MIN=28
CONFIG_ARCH_MMAP_RND_BITS_MAX=32
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN=8
CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX=16
CONFIG_GENERIC_ISA_DMA=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_BUG_RELATIVE_POINTERS=y
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_ARCH_HAS_CPU_RELAX=y
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_NR_GPIO=1024
CONFIG_ARCH_SUSPEND_POSSIBLE=y
CONFIG_AUDIT_ARCH=y
CONFIG_ARCH_SUPPORTS_UPROBES=y
CONFIG_FIX_EARLYCON_MEM=y
CONFIG_PGTABLE_LEVELS=4
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y

#
# Processor type and features
#
# CONFIG_SMP is not set
CONFIG_X86_FEATURE_NAMES=y
CONFIG_X86_MPPARSE=y
# CONFIG_GOLDFISH is not set
# CONFIG_X86_CPU_RESCTRL is not set
# CONFIG_X86_EXTENDED_PLATFORM is not set
# CONFIG_SCHED_OMIT_FRAME_POINTER is not set
# CONFIG_HYPERVISOR_GUEST is not set
# CONFIG_MK8 is not set
# CONFIG_MPSC is not set
# CONFIG_MCORE2 is not set
# CONFIG_MATOM is not set
CONFIG_GENERIC_CPU=y
CONFIG_X86_INTERNODE_CACHE_SHIFT=6
CONFIG_X86_L1_CACHE_SHIFT=6
CONFIG_X86_TSC=y
CONFIG_X86_CMPXCHG64=y
CONFIG_X86_CMOV=y
CONFIG_X86_MINIMUM_CPU_FAMILY=64
CONFIG_X86_DEBUGCTLMSR=y
CONFIG_IA32_FEAT_CTL=y
CONFIG_X86_VMX_FEATURE_NAMES=y
CONFIG_CPU_SUP_INTEL=y
CONFIG_CPU_SUP_AMD=y
CONFIG_CPU_SUP_HYGON=y
CONFIG_CPU_SUP_CENTAUR=y
CONFIG_CPU_SUP_ZHAOXIN=y
CONFIG_HPET_TIMER=y
CONFIG_DMI=y
CONFIG_NR_CPUS_RANGE_BEGIN=1
CONFIG_NR_CPUS_RANGE_END=1
CONFIG_NR_CPUS_DEFAULT=1
CONFIG_NR_CPUS=1
CONFIG_UP_LATE_INIT=y
CONFIG_X86_LOCAL_APIC=y
CONFIG_X86_IO_APIC=y
# CONFIG_X86_REROUTE_FOR_BROKEN_BOOT_IRQS is not set
# CONFIG_X86_MCE is not set

#
# Performance monitoring
#
# CONFIG_PERF_EVENTS_AMD_POWER is not set
# CONFIG_PERF_EVENTS_AMD_UNCORE is not set
# CONFIG_PERF_EVENTS_AMD_BRS is not set
# end of Performance monitoring

CONFIG_X86_16BIT=y
CONFIG_X86_ESPFIX64=y
CONFIG_X86_VSYSCALL_EMULATION=y
# CONFIG_X86_IOPL_IOPERM is not set
# CONFIG_MICROCODE is not set
# CONFIG_X86_MSR is not set
# CONFIG_X86_CPUID is not set
# CONFIG_X86_5LEVEL is not set
CONFIG_X86_DIRECT_GBPAGES=y
# CONFIG_AMD_MEM_ENCRYPT is not set
CONFIG_ARCH_SPARSEMEM_ENABLE=y
CONFIG_ARCH_SPARSEMEM_DEFAULT=y
CONFIG_ILLEGAL_POINTER_VALUE=0xdead000000000000
# CONFIG_X86_CHECK_BIOS_CORRUPTION is not set
CONFIG_MTRR=y
# CONFIG_MTRR_SANITIZER is not set
CONFIG_X86_PAT=y
CONFIG_ARCH_USES_PG_UNCACHED=y
CONFIG_X86_UMIP=y
CONFIG_CC_HAS_IBT=y
# CONFIG_X86_KERNEL_IBT is not set
# CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is not set
CONFIG_X86_INTEL_TSX_MODE_OFF=y
# CONFIG_X86_INTEL_TSX_MODE_ON is not set
# CONFIG_X86_INTEL_TSX_MODE_AUTO is not set
# CONFIG_HZ_100 is not set
CONFIG_HZ_250=y
# CONFIG_HZ_300 is not set
# CONFIG_HZ_1000 is not set
CONFIG_HZ=250
# CONFIG_KEXEC is not set
# CONFIG_CRASH_DUMP is not set
CONFIG_PHYSICAL_START=0x1000000
# CONFIG_RELOCATABLE is not set
CONFIG_PHYSICAL_ALIGN=0x200000
CONFIG_LEGACY_VSYSCALL_XONLY=y
# CONFIG_LEGACY_VSYSCALL_NONE is not set
# CONFIG_CMDLINE_BOOL is not set
CONFIG_MODIFY_LDT_SYSCALL=y
# CONFIG_STRICT_SIGALTSTACK_SIZE is not set
CONFIG_HAVE_LIVEPATCH=y
# end of Processor type and features

CONFIG_CC_HAS_SLS=y
CONFIG_CC_HAS_RETURN_THUNK=y
# CONFIG_SPECULATION_MITIGATIONS is not set
CONFIG_ARCH_HAS_ADD_PAGES=y
CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE=y

#
# Power management and ACPI options
#
# CONFIG_SUSPEND is not set
# CONFIG_PM is not set
CONFIG_ARCH_SUPPORTS_ACPI=y
# CONFIG_ACPI is not set

#
# CPU Frequency scaling
#
# CONFIG_CPU_FREQ is not set
# end of CPU Frequency scaling

#
# CPU Idle
#
# CONFIG_CPU_IDLE is not set
# end of CPU Idle
# end of Power management and ACPI options

#
# Bus options (PCI etc.)
#
CONFIG_ISA_DMA_API=y
# end of Bus options (PCI etc.)

#
# Binary Emulations
#
# CONFIG_IA32_EMULATION is not set
# CONFIG_X86_X32_ABI is not set
# end of Binary Emulations

CONFIG_HAVE_KVM=y
# CONFIG_VIRTUALIZATION is not set
CONFIG_AS_AVX512=y
CONFIG_AS_SHA1_NI=y
CONFIG_AS_SHA256_NI=y
CONFIG_AS_TPAUSE=y

#
# General architecture-dependent options
#
CONFIG_GENERIC_ENTRY=y
# CONFIG_JUMP_LABEL is not set
# CONFIG_STATIC_CALL_SELFTEST is not set
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS=y
CONFIG_ARCH_USE_BUILTIN_BSWAP=y
CONFIG_HAVE_IOREMAP_PROT=y
CONFIG_HAVE_KPROBES=y
CONFIG_HAVE_KRETPROBES=y
CONFIG_HAVE_OPTPROBES=y
CONFIG_HAVE_KPROBES_ON_FTRACE=y
CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE=y
CONFIG_HAVE_FUNCTION_ERROR_INJECTION=y
CONFIG_HAVE_NMI=y
CONFIG_TRACE_IRQFLAGS_SUPPORT=y
CONFIG_TRACE_IRQFLAGS_NMI_SUPPORT=y
CONFIG_HAVE_ARCH_TRACEHOOK=y
CONFIG_HAVE_DMA_CONTIGUOUS=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y
CONFIG_ARCH_HAS_FORTIFY_SOURCE=y
CONFIG_ARCH_HAS_SET_MEMORY=y
CONFIG_ARCH_HAS_SET_DIRECT_MAP=y
CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST=y
CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT=y
CONFIG_ARCH_WANTS_NO_INSTR=y
CONFIG_HAVE_ASM_MODVERSIONS=y
CONFIG_HAVE_REGS_AND_STACK_ACCESS_API=y
CONFIG_HAVE_RSEQ=y
CONFIG_HAVE_RUST=y
CONFIG_HAVE_FUNCTION_ARG_ACCESS_API=y
CONFIG_HAVE_HW_BREAKPOINT=y
CONFIG_HAVE_MIXED_BREAKPOINTS_REGS=y
CONFIG_HAVE_USER_RETURN_NOTIFIER=y
CONFIG_HAVE_PERF_EVENTS_NMI=y
CONFIG_HAVE_HARDLOCKUP_DETECTOR_PERF=y
CONFIG_HAVE_PERF_REGS=y
CONFIG_HAVE_PERF_USER_STACK_DUMP=y
CONFIG_HAVE_ARCH_JUMP_LABEL=y
CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE=y
CONFIG_MMU_GATHER_MERGE_VMAS=y
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG=y
CONFIG_ARCH_HAS_NMI_SAFE_THIS_CPU_OPS=y
CONFIG_HAVE_ALIGNED_STRUCT_PAGE=y
CONFIG_HAVE_CMPXCHG_LOCAL=y
CONFIG_HAVE_CMPXCHG_DOUBLE=y
CONFIG_HAVE_ARCH_SECCOMP=y
CONFIG_HAVE_ARCH_SECCOMP_FILTER=y
# CONFIG_SECCOMP is not set
CONFIG_HAVE_ARCH_STACKLEAK=y
CONFIG_HAVE_STACKPROTECTOR=y
# CONFIG_STACKPROTECTOR is not set
CONFIG_ARCH_SUPPORTS_LTO_CLANG=y
CONFIG_ARCH_SUPPORTS_LTO_CLANG_THIN=y
CONFIG_LTO_NONE=y
CONFIG_ARCH_SUPPORTS_CFI_CLANG=y
CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES=y
CONFIG_HAVE_CONTEXT_TRACKING_USER=y
CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK=y
CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN=y
CONFIG_HAVE_IRQ_TIME_ACCOUNTING=y
CONFIG_HAVE_MOVE_PUD=y
CONFIG_HAVE_MOVE_PMD=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE=y
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD=y
CONFIG_HAVE_ARCH_HUGE_VMAP=y
CONFIG_HAVE_ARCH_HUGE_VMALLOC=y
CONFIG_ARCH_WANT_HUGE_PMD_SHARE=y
CONFIG_HAVE_ARCH_SOFT_DIRTY=y
CONFIG_HAVE_MOD_ARCH_SPECIFIC=y
CONFIG_MODULES_USE_ELF_RELA=y
CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK=y
CONFIG_HAVE_SOFTIRQ_ON_OWN_STACK=y
CONFIG_SOFTIRQ_ON_OWN_STACK=y
CONFIG_ARCH_HAS_ELF_RANDOMIZE=y
CONFIG_HAVE_ARCH_MMAP_RND_BITS=y
CONFIG_HAVE_EXIT_THREAD=y
CONFIG_ARCH_MMAP_RND_BITS=28
CONFIG_PAGE_SIZE_LESS_THAN_64KB=y
CONFIG_PAGE_SIZE_LESS_THAN_256KB=y
CONFIG_HAVE_OBJTOOL=y
CONFIG_HAVE_JUMP_LABEL_HACK=y
CONFIG_HAVE_NOINSTR_HACK=y
CONFIG_HAVE_NOINSTR_VALIDATION=y
CONFIG_HAVE_UACCESS_VALIDATION=y
CONFIG_HAVE_STACK_VALIDATION=y
CONFIG_HAVE_RELIABLE_STACKTRACE=y
# CONFIG_COMPAT_32BIT_TIME is not set
CONFIG_HAVE_ARCH_VMAP_STACK=y
# CONFIG_VMAP_STACK is not set
CONFIG_HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET=y
CONFIG_RANDOMIZE_KSTACK_OFFSET=y
# CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT is not set
CONFIG_ARCH_HAS_STRICT_KERNEL_RWX=y
CONFIG_STRICT_KERNEL_RWX=y
CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS=y
CONFIG_ARCH_HAS_MEM_ENCRYPT=y
CONFIG_HAVE_STATIC_CALL=y
CONFIG_HAVE_STATIC_CALL_INLINE=y
CONFIG_HAVE_PREEMPT_DYNAMIC=y
CONFIG_HAVE_PREEMPT_DYNAMIC_CALL=y
CONFIG_ARCH_WANT_LD_ORPHAN_WARN=y
CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC=y
CONFIG_ARCH_SUPPORTS_PAGE_TABLE_CHECK=y
CONFIG_ARCH_HAS_ELFCORE_COMPAT=y
CONFIG_ARCH_HAS_PARANOID_L1D_FLUSH=y
CONFIG_DYNAMIC_SIGFRAME=y
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG=y

#
# GCOV-based kernel profiling
#
CONFIG_ARCH_HAS_GCOV_PROFILE_ALL=y
# end of GCOV-based kernel profiling

CONFIG_HAVE_GCC_PLUGINS=y
# CONFIG_GCC_PLUGINS is not set
# end of General architecture-dependent options

CONFIG_RT_MUTEXES=y
CONFIG_BASE_SMALL=0
# CONFIG_MODULES is not set
CONFIG_BLOCK=y
# CONFIG_BLOCK_LEGACY_AUTOLOAD is not set
# CONFIG_BLK_DEV_BSGLIB is not set
# CONFIG_BLK_DEV_INTEGRITY is not set
# CONFIG_BLK_DEV_ZONED is not set
# CONFIG_BLK_WBT is not set
# CONFIG_BLK_SED_OPAL is not set
# CONFIG_BLK_INLINE_ENCRYPTION is not set

#
# Partition Types
#
# CONFIG_PARTITION_ADVANCED is not set
CONFIG_MSDOS_PARTITION=y
CONFIG_EFI_PARTITION=y
# end of Partition Types

#
# IO Schedulers
#
# CONFIG_MQ_IOSCHED_DEADLINE is not set
# CONFIG_MQ_IOSCHED_KYBER is not set
# CONFIG_IOSCHED_BFQ is not set
# end of IO Schedulers

CONFIG_INLINE_SPIN_UNLOCK_IRQ=y
CONFIG_INLINE_READ_UNLOCK=y
CONFIG_INLINE_READ_UNLOCK_IRQ=y
CONFIG_INLINE_WRITE_UNLOCK=y
CONFIG_INLINE_WRITE_UNLOCK_IRQ=y
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y
CONFIG_ARCH_USE_QUEUED_SPINLOCKS=y
CONFIG_ARCH_USE_QUEUED_RWLOCKS=y
CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE=y
CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE=y
CONFIG_ARCH_HAS_SYSCALL_WRAPPER=y

#
# Executable file formats
#
# CONFIG_BINFMT_ELF is not set
# CONFIG_BINFMT_SCRIPT is not set
# CONFIG_BINFMT_MISC is not set
CONFIG_COREDUMP=y
# end of Executable file formats

#
# Memory Management options
#
# CONFIG_SWAP is not set

#
# SLAB allocator options
#
# CONFIG_SLAB is not set
CONFIG_SLUB=y
# CONFIG_SLAB_MERGE_DEFAULT is not set
# CONFIG_SLAB_FREELIST_RANDOM is not set
# CONFIG_SLAB_FREELIST_HARDENED is not set
# CONFIG_SLUB_STATS is not set
# end of SLAB allocator options

# CONFIG_SHUFFLE_PAGE_ALLOCATOR is not set
# CONFIG_COMPAT_BRK is not set
CONFIG_SPARSEMEM=y
CONFIG_SPARSEMEM_EXTREME=y
CONFIG_SPARSEMEM_VMEMMAP_ENABLE=y
# CONFIG_SPARSEMEM_VMEMMAP is not set
CONFIG_HAVE_FAST_GUP=y
CONFIG_EXCLUSIVE_SYSTEM_RAM=y
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG=y
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
# CONFIG_COMPACTION is not set
# CONFIG_PAGE_REPORTING is not set
CONFIG_PHYS_ADDR_T_64BIT=y
# CONFIG_KSM is not set
CONFIG_DEFAULT_MMAP_MIN_ADDR=4096
CONFIG_ARCH_WANT_GENERAL_HUGETLB=y
CONFIG_ARCH_WANTS_THP_SWAP=y
# CONFIG_TRANSPARENT_HUGEPAGE is not set
CONFIG_NEED_PER_CPU_KM=y
CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK=y
CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK=y
CONFIG_HAVE_SETUP_PER_CPU_AREA=y
# CONFIG_CMA is not set
CONFIG_GENERIC_EARLY_IOREMAP=y
# CONFIG_IDLE_PAGE_TRACKING is not set
CONFIG_ARCH_HAS_CACHE_LINE_SIZE=y
CONFIG_ARCH_HAS_CURRENT_STACK_POINTER=y
CONFIG_ARCH_HAS_PTE_DEVMAP=y
CONFIG_ZONE_DMA=y
CONFIG_ZONE_DMA32=y
CONFIG_VM_EVENT_COUNTERS=y
# CONFIG_PERCPU_STATS is not set

#
# GUP_TEST needs to have DEBUG_FS enabled
#
CONFIG_ARCH_HAS_PTE_SPECIAL=y
CONFIG_SECRETMEM=y
# CONFIG_ANON_VMA_NAME is not set
# CONFIG_USERFAULTFD is not set
# CONFIG_LRU_GEN is not set

#
# Data Access Monitoring
#
# CONFIG_DAMON is not set
# end of Data Access Monitoring
# end of Memory Management options

# CONFIG_NET is not set

#
# Device Drivers
#
CONFIG_HAVE_EISA=y
# CONFIG_EISA is not set
CONFIG_HAVE_PCI=y
# CONFIG_PCI is not set
# CONFIG_PCCARD is not set

#
# Generic Driver Options
#
# CONFIG_UEVENT_HELPER is not set
# CONFIG_DEVTMPFS is not set
# CONFIG_STANDALONE is not set
# CONFIG_PREVENT_FIRMWARE_BUILD is not set

#
# Firmware loader
#
CONFIG_FW_LOADER=y
CONFIG_EXTRA_FIRMWARE=""
# CONFIG_FW_LOADER_USER_HELPER is not set
# CONFIG_FW_LOADER_COMPRESS is not set
# CONFIG_FW_UPLOAD is not set
# end of Firmware loader

CONFIG_ALLOW_DEV_COREDUMP=y
CONFIG_GENERIC_CPU_AUTOPROBE=y
CONFIG_GENERIC_CPU_VULNERABILITIES=y
# end of Generic Driver Options

#
# Bus devices
#
# CONFIG_ARM_INTEGRATOR_LM is not set
# CONFIG_BT1_APB is not set
# CONFIG_BT1_AXI is not set
# CONFIG_HISILICON_LPC is not set
# CONFIG_INTEL_IXP4XX_EB is not set
# CONFIG_QCOM_EBI2 is not set
# CONFIG_MHI_BUS is not set
# CONFIG_MHI_BUS_EP is not set
# end of Bus devices

#
# Firmware Drivers
#

#
# ARM System Control and Management Interface Protocol
#
# CONFIG_ARM_SCMI_PROTOCOL is not set
# end of ARM System Control and Management Interface Protocol

# CONFIG_EDD is not set
CONFIG_FIRMWARE_MEMMAP=y
# CONFIG_DMIID is not set
# CONFIG_DMI_SYSFS is not set
CONFIG_DMI_SCAN_MACHINE_NON_EFI_FALLBACK=y
# CONFIG_FW_CFG_SYSFS is not set
# CONFIG_SYSFB_SIMPLEFB is not set
# CONFIG_BCM47XX_NVRAM is not set
# CONFIG_GOOGLE_FIRMWARE is not set

#
# Tegra firmware driver
#
# end of Tegra firmware driver
# end of Firmware Drivers

# CONFIG_GNSS is not set
# CONFIG_MTD is not set
# CONFIG_OF is not set
CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT=y
# CONFIG_PARPORT is not set
# CONFIG_BLK_DEV is not set

#
# NVME Support
#
# CONFIG_NVME_FC is not set
# end of NVME Support

#
# Misc devices
#
# CONFIG_DUMMY_IRQ is not set
# CONFIG_ATMEL_SSC is not set
# CONFIG_ENCLOSURE_SERVICES is not set
# CONFIG_QCOM_COINCELL is not set
# CONFIG_SRAM is not set
# CONFIG_XILINX_SDFEC is not set
# CONFIG_C2PORT is not set

#
# EEPROM support
#
# CONFIG_EEPROM_93CX6 is not set
# end of EEPROM support

#
# Texas Instruments shared transport line discipline
#
# end of Texas Instruments shared transport line discipline

#
# Altera FPGA firmware download module (requires I2C)
#
# CONFIG_ECHO is not set
# CONFIG_PVPANIC is not set
# end of Misc devices

#
# SCSI device support
#
CONFIG_SCSI_MOD=y
# CONFIG_RAID_ATTRS is not set
# CONFIG_SCSI is not set
# end of SCSI device support

# CONFIG_ATA is not set
# CONFIG_MD is not set
# CONFIG_TARGET_CORE is not set

#
# IEEE 1394 (FireWire) support
#
# CONFIG_FIREWIRE is not set
# end of IEEE 1394 (FireWire) support

# CONFIG_MACINTOSH_DRIVERS is not set

#
# Input device support
#
CONFIG_INPUT=y
# CONFIG_INPUT_FF_MEMLESS is not set
# CONFIG_INPUT_SPARSEKMAP is not set
# CONFIG_INPUT_MATRIXKMAP is not set

#
# Userland interfaces
#
# CONFIG_INPUT_MOUSEDEV is not set
# CONFIG_INPUT_JOYDEV is not set
# CONFIG_INPUT_EVDEV is not set
# CONFIG_INPUT_EVBUG is not set

#
# Input Device Drivers
#
# CONFIG_INPUT_KEYBOARD is not set
# CONFIG_INPUT_MOUSE is not set
# CONFIG_INPUT_JOYSTICK is not set
# CONFIG_INPUT_TABLET is not set
# CONFIG_INPUT_TOUCHSCREEN is not set
# CONFIG_INPUT_MISC is not set
# CONFIG_RMI4_CORE is not set

#
# Hardware I/O ports
#
# CONFIG_SERIO is not set
CONFIG_ARCH_MIGHT_HAVE_PC_SERIO=y
# CONFIG_GAMEPORT is not set
# end of Hardware I/O ports
# end of Input device support

#
# Character devices
#
CONFIG_TTY=y
CONFIG_VT=y
CONFIG_CONSOLE_TRANSLATIONS=y
CONFIG_VT_CONSOLE=y
CONFIG_HW_CONSOLE=y
# CONFIG_VT_HW_CONSOLE_BINDING is not set
CONFIG_UNIX98_PTYS=y
# CONFIG_LEGACY_PTYS is not set
# CONFIG_LDISC_AUTOLOAD is not set

#
# Serial drivers
#
# CONFIG_SERIAL_8250 is not set

#
# Non-8250 serial port support
#
# CONFIG_SERIAL_AMBA_PL010 is not set
# CONFIG_SERIAL_MESON is not set
# CONFIG_SERIAL_CLPS711X is not set
# CONFIG_SERIAL_SAMSUNG is not set
# CONFIG_SERIAL_TEGRA is not set
# CONFIG_SERIAL_IMX is not set
# CONFIG_SERIAL_UARTLITE is not set
# CONFIG_SERIAL_SH_SCI is not set
# CONFIG_SERIAL_MSM is not set
# CONFIG_SERIAL_VT8500 is not set
# CONFIG_SERIAL_OMAP is not set
# CONFIG_SERIAL_LANTIQ is not set
# CONFIG_SERIAL_SCCNXP is not set
# CONFIG_SERIAL_TIMBERDALE is not set
# CONFIG_SERIAL_BCM63XX is not set
# CONFIG_SERIAL_ALTERA_JTAGUART is not set
# CONFIG_SERIAL_ALTERA_UART is not set
# CONFIG_SERIAL_MXS_AUART is not set
# CONFIG_SERIAL_MPS2_UART is not set
# CONFIG_SERIAL_ARC is not set
# CONFIG_SERIAL_FSL_LPUART is not set
# CONFIG_SERIAL_FSL_LINFLEXUART is not set
# CONFIG_SERIAL_ST_ASC is not set
# CONFIG_SERIAL_STM32 is not set
# CONFIG_SERIAL_OWL is not set
# CONFIG_SERIAL_RDA is not set
# CONFIG_SERIAL_LITEUART is not set
# CONFIG_SERIAL_SUNPLUS is not set
# end of Serial drivers

# CONFIG_SERIAL_NONSTANDARD is not set
# CONFIG_NULL_TTY is not set
# CONFIG_SERIAL_DEV_BUS is not set
# CONFIG_VIRTIO_CONSOLE is not set
# CONFIG_IPMI_HANDLER is not set
# CONFIG_ASPEED_KCS_IPMI_BMC is not set
# CONFIG_NPCM7XX_KCS_IPMI_BMC is not set
# CONFIG_HW_RANDOM is not set
# CONFIG_MWAVE is not set
# CONFIG_DEVMEM is not set
# CONFIG_NVRAM is not set
# CONFIG_HANGCHECK_TIMER is not set
# CONFIG_TCG_TPM is not set
# CONFIG_TELCLOCK is not set
# CONFIG_RANDOM_TRUST_CPU is not set
# CONFIG_RANDOM_TRUST_BOOTLOADER is not set
# end of Character devices

#
# I2C support
#
# CONFIG_I2C is not set
# end of I2C support

# CONFIG_I3C is not set
# CONFIG_SPI is not set
# CONFIG_SPMI is not set
# CONFIG_HSI is not set
# CONFIG_PPS is not set

#
# PTP clock support
#
CONFIG_PTP_1588_CLOCK_OPTIONAL=y

#
# Enable PHYLIB and NETWORK_PHY_TIMESTAMPING to see the additional clocks.
#
# end of PTP clock support

# CONFIG_PINCTRL is not set
# CONFIG_GPIOLIB is not set
# CONFIG_W1 is not set
# CONFIG_POWER_RESET is not set
# CONFIG_POWER_SUPPLY is not set
# CONFIG_HWMON is not set
# CONFIG_THERMAL is not set
# CONFIG_WATCHDOG is not set
CONFIG_SSB_POSSIBLE=y
# CONFIG_SSB is not set
CONFIG_BCMA_POSSIBLE=y
# CONFIG_BCMA is not set

#
# Multifunction device drivers
#
# CONFIG_MFD_SUN4I_GPADC is not set
# CONFIG_MFD_AT91_USART is not set
# CONFIG_MFD_MADERA is not set
# CONFIG_MFD_EXYNOS_LPASS is not set
# CONFIG_MFD_MXS_LRADC is not set
# CONFIG_MFD_MX25_TSADC is not set
# CONFIG_HTC_PASIC3 is not set
# CONFIG_MFD_KEMPLD is not set
# CONFIG_MFD_MT6397 is not set
# CONFIG_MFD_PM8XXX is not set
# CONFIG_MFD_SM501 is not set
# CONFIG_ABX500_CORE is not set
# CONFIG_MFD_SUN6I_PRCM is not set
# CONFIG_MFD_SYSCON is not set
# CONFIG_MFD_TI_AM335X_TSCADC is not set
# CONFIG_MFD_TQMX86 is not set
# CONFIG_MFD_STM32_LPTIMER is not set
# CONFIG_MFD_STM32_TIMERS is not set
# end of Multifunction device drivers

# CONFIG_REGULATOR is not set
# CONFIG_RC_CORE is not set

#
# CEC support
#
# CONFIG_MEDIA_CEC_SUPPORT is not set
# end of CEC support

# CONFIG_MEDIA_SUPPORT is not set

#
# Graphics support
#
# CONFIG_IMX_IPUV3_CORE is not set
# CONFIG_DRM is not set

#
# ARM devices
#
# end of ARM devices

#
# Frame buffer Devices
#
# CONFIG_FB is not set
# CONFIG_MMP_DISP is not set
# end of Frame buffer Devices

#
# Backlight & LCD device support
#
# CONFIG_LCD_CLASS_DEVICE is not set
# CONFIG_BACKLIGHT_CLASS_DEVICE is not set
# end of Backlight & LCD device support

#
# Console display driver support
#
CONFIG_VGA_CONSOLE=y
CONFIG_DUMMY_CONSOLE=y
CONFIG_DUMMY_CONSOLE_COLUMNS=80
CONFIG_DUMMY_CONSOLE_ROWS=25
# end of Console display driver support
# end of Graphics support

# CONFIG_SOUND is not set

#
# HID support
#
# CONFIG_HID is not set
# end of HID support

CONFIG_USB_OHCI_LITTLE_ENDIAN=y
# CONFIG_USB_SUPPORT is not set
# CONFIG_MMC is not set
# CONFIG_MEMSTICK is not set
# CONFIG_NEW_LEDS is not set
# CONFIG_ACCESSIBILITY is not set
CONFIG_EDAC_ATOMIC_SCRUB=y
CONFIG_EDAC_SUPPORT=y
CONFIG_RTC_LIB=y
CONFIG_RTC_MC146818_LIB=y
# CONFIG_RTC_CLASS is not set
# CONFIG_DMADEVICES is not set

#
# DMABUF options
#
# CONFIG_SYNC_FILE is not set
# CONFIG_DMABUF_HEAPS is not set
# end of DMABUF options

# CONFIG_AUXDISPLAY is not set
# CONFIG_UIO is not set
# CONFIG_VFIO is not set
# CONFIG_VIRT_DRIVERS is not set
# CONFIG_VIRTIO_MENU is not set
# CONFIG_VHOST_MENU is not set

#
# Microsoft Hyper-V guest support
#
# end of Microsoft Hyper-V guest support

# CONFIG_GREYBUS is not set
# CONFIG_COMEDI is not set
# CONFIG_STAGING is not set
# CONFIG_CHROME_PLATFORMS is not set
# CONFIG_MELLANOX_PLATFORM is not set
# CONFIG_OLPC_XO175 is not set
# CONFIG_SURFACE_PLATFORMS is not set
# CONFIG_X86_PLATFORM_DEVICES is not set
# CONFIG_COMMON_CLK is not set
# CONFIG_HWSPINLOCK is not set

#
# Clock Source drivers
#
CONFIG_CLKEVT_I8253=y
CONFIG_I8253_LOCK=y
CONFIG_CLKBLD_I8253=y
# CONFIG_BCM2835_TIMER is not set
# CONFIG_BCM_KONA_TIMER is not set
# CONFIG_DAVINCI_TIMER is not set
# CONFIG_DIGICOLOR_TIMER is not set
# CONFIG_OMAP_DM_TIMER is not set
# CONFIG_DW_APB_TIMER is not set
# CONFIG_FTTMR010_TIMER is not set
# CONFIG_IXP4XX_TIMER is not set
# CONFIG_MESON6_TIMER is not set
# CONFIG_OWL_TIMER is not set
# CONFIG_RDA_TIMER is not set
# CONFIG_SUN4I_TIMER is not set
# CONFIG_TEGRA_TIMER is not set
# CONFIG_VT8500_TIMER is not set
# CONFIG_NPCM7XX_TIMER is not set
# CONFIG_ASM9260_TIMER is not set
# CONFIG_CLKSRC_DBX500_PRCMU is not set
# CONFIG_CLPS711X_TIMER is not set
# CONFIG_MXS_TIMER is not set
# CONFIG_NSPIRE_TIMER is not set
# CONFIG_INTEGRATOR_AP_TIMER is not set
# CONFIG_CLKSRC_PISTACHIO is not set
# CONFIG_CLKSRC_STM32_LP is not set
# CONFIG_ARMV7M_SYSTICK is not set
# CONFIG_ATMEL_PIT is not set
# CONFIG_ATMEL_ST is not set
# CONFIG_CLKSRC_SAMSUNG_PWM is not set
# CONFIG_FSL_FTM_TIMER is not set
# CONFIG_OXNAS_RPS_TIMER is not set
# CONFIG_MTK_TIMER is not set
# CONFIG_SH_TIMER_CMT is not set
# CONFIG_SH_TIMER_MTU2 is not set
# CONFIG_RENESAS_OSTM is not set
# CONFIG_SH_TIMER_TMU is not set
# CONFIG_EM_TIMER_STI is not set
# CONFIG_CLKSRC_PXA is not set
# CONFIG_TIMER_IMX_SYS_CTR is not set
# CONFIG_CLKSRC_ST_LPC is not set
# CONFIG_GXP_TIMER is not set
# CONFIG_MSC313E_TIMER is not set
# CONFIG_MICROCHIP_PIT64B is not set
# end of Clock Source drivers

# CONFIG_MAILBOX is not set
# CONFIG_IOMMU_SUPPORT is not set

#
# Remoteproc drivers
#
# CONFIG_REMOTEPROC is not set
# end of Remoteproc drivers

#
# Rpmsg drivers
#
# CONFIG_RPMSG_VIRTIO is not set
# end of Rpmsg drivers

#
# SOC (System On Chip) specific Drivers
#

#
# Amlogic SoC drivers
#
# CONFIG_MESON_CANVAS is not set
# CONFIG_MESON_CLK_MEASURE is not set
# CONFIG_MESON_GX_SOCINFO is not set
# CONFIG_MESON_MX_SOCINFO is not set
# end of Amlogic SoC drivers

#
# Apple SoC drivers
#
# CONFIG_APPLE_SART is not set
# end of Apple SoC drivers

#
# ASPEED SoC drivers
#
# CONFIG_ASPEED_LPC_CTRL is not set
# CONFIG_ASPEED_LPC_SNOOP is not set
# CONFIG_ASPEED_UART_ROUTING is not set
# CONFIG_ASPEED_P2A_CTRL is not set
# CONFIG_ASPEED_SOCINFO is not set
# end of ASPEED SoC drivers

# CONFIG_AT91_SOC_ID is not set
# CONFIG_AT91_SOC_SFR is not set

#
# Broadcom SoC drivers
#
# CONFIG_SOC_BCM63XX is not set
# CONFIG_SOC_BRCMSTB is not set
# end of Broadcom SoC drivers

#
# NXP/Freescale QorIQ SoC drivers
#
# end of NXP/Freescale QorIQ SoC drivers

#
# fujitsu SoC drivers
#
# end of fujitsu SoC drivers

#
# i.MX SoC drivers
#
# CONFIG_SOC_IMX8M is not set
# CONFIG_SOC_IMX9 is not set
# end of i.MX SoC drivers

#
# IXP4xx SoC drivers
#
# CONFIG_IXP4XX_QMGR is not set
# CONFIG_IXP4XX_NPE is not set
# end of IXP4xx SoC drivers

#
# Enable LiteX SoC Builder specific drivers
#
# CONFIG_LITEX_SOC_CONTROLLER is not set
# end of Enable LiteX SoC Builder specific drivers

#
# MediaTek SoC drivers
#
# CONFIG_MTK_CMDQ is not set
# CONFIG_MTK_DEVAPC is not set
# CONFIG_MTK_INFRACFG is not set
# CONFIG_MTK_MMSYS is not set
# end of MediaTek SoC drivers

#
# Qualcomm SoC drivers
#
# CONFIG_QCOM_GENI_SE is not set
# CONFIG_QCOM_GSBI is not set
# CONFIG_QCOM_LLCC is not set
# CONFIG_QCOM_RPMH is not set
# CONFIG_QCOM_SPM is not set
# CONFIG_QCOM_ICC_BWMON is not set
# end of Qualcomm SoC drivers

# CONFIG_SOC_RENESAS is not set
# CONFIG_ROCKCHIP_GRF is not set
# CONFIG_SOC_SAMSUNG is not set
# CONFIG_SOC_TI is not set
# CONFIG_UX500_SOC_ID is not set

#
# Xilinx SoC drivers
#
# end of Xilinx SoC drivers
# end of SOC (System On Chip) specific Drivers

# CONFIG_PM_DEVFREQ is not set
# CONFIG_EXTCON is not set
# CONFIG_MEMORY is not set
# CONFIG_IIO is not set
# CONFIG_PWM is not set

#
# IRQ chip support
#
# CONFIG_AL_FIC is not set
# CONFIG_RENESAS_INTC_IRQPIN is not set
# CONFIG_RENESAS_IRQC is not set
# CONFIG_RENESAS_RZA1_IRQC is not set
# CONFIG_RENESAS_RZG2L_IRQC is not set
# CONFIG_SL28CPLD_INTC is not set
# CONFIG_TS4800_IRQ is not set
# CONFIG_INGENIC_TCU_IRQ is not set
# CONFIG_IRQ_UNIPHIER_AIDET is not set
# CONFIG_MESON_IRQ_GPIO is not set
# CONFIG_IMX_IRQSTEER is not set
# CONFIG_IMX_INTMUX is not set
# CONFIG_EXYNOS_IRQ_COMBINER is not set
# CONFIG_MST_IRQ is not set
# CONFIG_MCHP_EIC is not set
# CONFIG_SUNPLUS_SP7021_INTC is not set
# end of IRQ chip support

# CONFIG_IPACK_BUS is not set
# CONFIG_RESET_CONTROLLER is not set

#
# PHY Subsystem
#
# CONFIG_GENERIC_PHY is not set
# CONFIG_PHY_PISTACHIO_USB is not set
# CONFIG_PHY_CAN_TRANSCEIVER is not set

#
# PHY drivers for Broadcom platforms
#
# CONFIG_PHY_BCM63XX_USBH is not set
# CONFIG_BCM_KONA_USB2_PHY is not set
# end of PHY drivers for Broadcom platforms

# CONFIG_PHY_HI6220_USB is not set
# CONFIG_PHY_HI3660_USB is not set
# CONFIG_PHY_HI3670_USB is not set
# CONFIG_PHY_HI3670_PCIE is not set
# CONFIG_PHY_HISTB_COMBPHY is not set
# CONFIG_PHY_HISI_INNO_USB2 is not set
# CONFIG_PHY_PXA_28NM_HSIC is not set
# CONFIG_PHY_PXA_28NM_USB2 is not set
# CONFIG_PHY_PXA_USB is not set
# CONFIG_PHY_MMP3_USB is not set
# CONFIG_PHY_MMP3_HSIC is not set
# CONFIG_PHY_MT7621_PCI is not set
# CONFIG_PHY_RALINK_USB is not set
# CONFIG_PHY_RCAR_GEN3_USB3 is not set
# CONFIG_PHY_ROCKCHIP_DPHY_RX0 is not set
# CONFIG_PHY_ROCKCHIP_PCIE is not set
# CONFIG_PHY_ROCKCHIP_SNPS_PCIE3 is not set
# CONFIG_PHY_EXYNOS_MIPI_VIDEO is not set
# CONFIG_PHY_SAMSUNG_USB2 is not set
# CONFIG_PHY_ST_SPEAR1310_MIPHY is not set
# CONFIG_PHY_ST_SPEAR1340_MIPHY is not set
# CONFIG_PHY_TEGRA194_P2U is not set
# CONFIG_PHY_DA8XX_USB is not set
# CONFIG_OMAP_CONTROL_PHY is not set
# CONFIG_TI_PIPE3 is not set
# CONFIG_PHY_INTEL_KEEMBAY_EMMC is not set
# CONFIG_PHY_INTEL_KEEMBAY_USB is not set
# CONFIG_PHY_INTEL_LGM_EMMC is not set
# CONFIG_PHY_XILINX_ZYNQMP is not set
# end of PHY Subsystem

# CONFIG_POWERCAP is not set
# CONFIG_MCB is not set

#
# Performance monitor support
#
# CONFIG_ARM_CCN is not set
# CONFIG_ARM_CMN is not set
# CONFIG_FSL_IMX8_DDR_PMU is not set
# CONFIG_XGENE_PMU is not set
# CONFIG_ARM_DMC620_PMU is not set
# CONFIG_MARVELL_CN10K_TAD_PMU is not set
# CONFIG_ALIBABA_UNCORE_DRW_PMU is not set
# CONFIG_MARVELL_CN10K_DDR_PMU is not set
# end of Performance monitor support

# CONFIG_RAS is not set

#
# Android
#
# CONFIG_ANDROID_BINDER_IPC is not set
# end of Android

# CONFIG_DAX is not set
# CONFIG_NVMEM is not set

#
# HW tracing support
#
# CONFIG_STM is not set
# CONFIG_INTEL_TH is not set
# end of HW tracing support

# CONFIG_FPGA is not set
# CONFIG_TEE is not set
# CONFIG_SIOX is not set
# CONFIG_SLIMBUS is not set
# CONFIG_INTERCONNECT is not set
# CONFIG_COUNTER is not set
# CONFIG_PECI is not set
# CONFIG_HTE is not set
# end of Device Drivers

#
# File systems
#
CONFIG_DCACHE_WORD_ACCESS=y
# CONFIG_VALIDATE_FS_PARSER is not set
# CONFIG_EXT2_FS is not set
# CONFIG_EXT3_FS is not set
# CONFIG_EXT4_FS is not set
# CONFIG_REISERFS_FS is not set
# CONFIG_JFS_FS is not set
# CONFIG_XFS_FS is not set
# CONFIG_GFS2_FS is not set
# CONFIG_BTRFS_FS is not set
# CONFIG_NILFS2_FS is not set
# CONFIG_F2FS_FS is not set
CONFIG_EXPORTFS=y
# CONFIG_EXPORTFS_BLOCK_OPS is not set
CONFIG_FILE_LOCKING=y
# CONFIG_FS_ENCRYPTION is not set
# CONFIG_FS_VERITY is not set
# CONFIG_DNOTIFY is not set
# CONFIG_INOTIFY_USER is not set
# CONFIG_FANOTIFY is not set
# CONFIG_QUOTA is not set
# CONFIG_AUTOFS4_FS is not set
# CONFIG_AUTOFS_FS is not set
# CONFIG_FUSE_FS is not set
# CONFIG_OVERLAY_FS is not set

#
# Caches
#
# CONFIG_FSCACHE is not set
# end of Caches

#
# CD-ROM/DVD Filesystems
#
# CONFIG_ISO9660_FS is not set
# CONFIG_UDF_FS is not set
# end of CD-ROM/DVD Filesystems

#
# DOS/FAT/EXFAT/NT Filesystems
#
# CONFIG_MSDOS_FS is not set
# CONFIG_VFAT_FS is not set
# CONFIG_EXFAT_FS is not set
# CONFIG_NTFS_FS is not set
# CONFIG_NTFS3_FS is not set
# end of DOS/FAT/EXFAT/NT Filesystems

#
# Pseudo filesystems
#
CONFIG_PROC_FS=y
# CONFIG_PROC_KCORE is not set
CONFIG_PROC_SYSCTL=y
CONFIG_PROC_PAGE_MONITOR=y
# CONFIG_PROC_CHILDREN is not set
CONFIG_PROC_PID_ARCH_STATUS=y
CONFIG_KERNFS=y
CONFIG_SYSFS=y
# CONFIG_TMPFS is not set
# CONFIG_HUGETLBFS is not set
CONFIG_ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP=y
CONFIG_ARCH_HAS_GIGANTIC_PAGE=y
# CONFIG_CONFIGFS_FS is not set
# end of Pseudo filesystems

# CONFIG_MISC_FILESYSTEMS is not set
# CONFIG_NLS is not set
# CONFIG_UNICODE is not set
CONFIG_IO_WQ=y
# end of File systems

#
# Security options
#
# CONFIG_KEYS is not set
# CONFIG_SECURITY_DMESG_RESTRICT is not set
# CONFIG_SECURITY is not set
# CONFIG_SECURITYFS is not set
CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR=y
# CONFIG_HARDENED_USERCOPY is not set
# CONFIG_FORTIFY_SOURCE is not set
# CONFIG_STATIC_USERMODEHELPER is not set
CONFIG_DEFAULT_SECURITY_DAC=y
CONFIG_LSM="landlock,lockdown,yama,loadpin,safesetid,integrity,bpf"

#
# Kernel hardening options
#

#
# Memory initialization
#
CONFIG_INIT_STACK_NONE=y
# CONFIG_INIT_ON_ALLOC_DEFAULT_ON is not set
# CONFIG_INIT_ON_FREE_DEFAULT_ON is not set
CONFIG_CC_HAS_ZERO_CALL_USED_REGS=y
# CONFIG_ZERO_CALL_USED_REGS is not set
# end of Memory initialization

CONFIG_RANDSTRUCT_NONE=y
# end of Kernel hardening options
# end of Security options

# CONFIG_CRYPTO is not set

#
# Library routines
#
# CONFIG_PACKING is not set
CONFIG_BITREVERSE=y
CONFIG_GENERIC_STRNCPY_FROM_USER=y
CONFIG_GENERIC_STRNLEN_USER=y
# CONFIG_CORDIC is not set
# CONFIG_PRIME_NUMBERS is not set
CONFIG_GENERIC_PCI_IOMAP=y
CONFIG_GENERIC_IOMAP=y
CONFIG_ARCH_USE_CMPXCHG_LOCKREF=y
CONFIG_ARCH_HAS_FAST_MULTIPLIER=y
CONFIG_ARCH_USE_SYM_ANNOTATIONS=y

#
# Crypto library routines
#
CONFIG_CRYPTO_LIB_BLAKE2S_GENERIC=y
# CONFIG_CRYPTO_LIB_CHACHA is not set
# CONFIG_CRYPTO_LIB_CURVE25519 is not set
CONFIG_CRYPTO_LIB_POLY1305_RSIZE=11
# CONFIG_CRYPTO_LIB_POLY1305 is not set
# end of Crypto library routines

# CONFIG_CRC_CCITT is not set
# CONFIG_CRC16 is not set
# CONFIG_CRC_T10DIF is not set
# CONFIG_CRC64_ROCKSOFT is not set
# CONFIG_CRC_ITU_T is not set
CONFIG_CRC32=y
# CONFIG_CRC32_SELFTEST is not set
CONFIG_CRC32_SLICEBY8=y
# CONFIG_CRC32_SLICEBY4 is not set
# CONFIG_CRC32_SARWATE is not set
# CONFIG_CRC32_BIT is not set
# CONFIG_CRC64 is not set
# CONFIG_CRC4 is not set
# CONFIG_CRC7 is not set
# CONFIG_LIBCRC32C is not set
# CONFIG_CRC8 is not set
# CONFIG_RANDOM32_SELFTEST is not set
# CONFIG_XZ_DEC is not set
CONFIG_HAS_IOMEM=y
CONFIG_HAS_IOPORT_MAP=y
CONFIG_HAS_DMA=y
CONFIG_NEED_SG_DMA_LENGTH=y
CONFIG_NEED_DMA_MAP_STATE=y
CONFIG_ARCH_DMA_ADDR_T_64BIT=y
CONFIG_SWIOTLB=y
# CONFIG_DMA_API_DEBUG is not set
# CONFIG_IRQ_POLL is not set
CONFIG_HAVE_GENERIC_VDSO=y
CONFIG_GENERIC_GETTIMEOFDAY=y
CONFIG_GENERIC_VDSO_TIME_NS=y
CONFIG_ARCH_HAS_PMEM_API=y
CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE=y
CONFIG_ARCH_HAS_COPY_MC=y
CONFIG_ARCH_STACKWALK=y
CONFIG_STACKDEPOT=y
CONFIG_SBITMAP=y
# CONFIG_PARMAN is not set
# CONFIG_OBJAGG is not set
# end of Library routines

#
# Kernel hacking
#

#
# printk and dmesg options
#
# CONFIG_PRINTK_TIME is not set
# CONFIG_PRINTK_CALLER is not set
# CONFIG_STACKTRACE_BUILD_ID is not set
CONFIG_CONSOLE_LOGLEVEL_DEFAULT=7
CONFIG_CONSOLE_LOGLEVEL_QUIET=4
CONFIG_MESSAGE_LOGLEVEL_DEFAULT=4
# CONFIG_DYNAMIC_DEBUG is not set
# CONFIG_DYNAMIC_DEBUG_CORE is not set
# CONFIG_SYMBOLIC_ERRNAME is not set
CONFIG_DEBUG_BUGVERBOSE=y
# end of printk and dmesg options

# CONFIG_DEBUG_KERNEL is not set

#
# Compile-time checks and compiler options
#
CONFIG_AS_HAS_NON_CONST_LEB128=y
CONFIG_FRAME_WARN=2048
# CONFIG_STRIP_ASM_SYMS is not set
# CONFIG_HEADERS_INSTALL is not set
CONFIG_DEBUG_SECTION_MISMATCH=y
CONFIG_SECTION_MISMATCH_WARN_ONLY=y
CONFIG_OBJTOOL=y
# end of Compile-time checks and compiler options

#
# Generic Kernel Debugging Instruments
#
# CONFIG_MAGIC_SYSRQ is not set
# CONFIG_DEBUG_FS is not set
CONFIG_HAVE_ARCH_KGDB=y
CONFIG_ARCH_HAS_UBSAN_SANITIZE_ALL=y
# CONFIG_UBSAN is not set
CONFIG_HAVE_ARCH_KCSAN=y
CONFIG_HAVE_KCSAN_COMPILER=y
# end of Generic Kernel Debugging Instruments

#
# Networking Debugging
#
# end of Networking Debugging

#
# Memory Debugging
#
# CONFIG_PAGE_EXTENSION is not set
CONFIG_SLUB_DEBUG=y
# CONFIG_SLUB_DEBUG_ON is not set
# CONFIG_PAGE_TABLE_CHECK is not set
# CONFIG_PAGE_POISONING is not set
# CONFIG_DEBUG_RODATA_TEST is not set
CONFIG_ARCH_HAS_DEBUG_WX=y
# CONFIG_DEBUG_WX is not set
CONFIG_GENERIC_PTDUMP=y
CONFIG_HAVE_DEBUG_KMEMLEAK=y
CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE=y
# CONFIG_DEBUG_VM_PGTABLE is not set
CONFIG_ARCH_HAS_DEBUG_VIRTUAL=y
CONFIG_DEBUG_MEMORY_INIT=y
CONFIG_ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP=y
CONFIG_HAVE_ARCH_KASAN=y
CONFIG_HAVE_ARCH_KASAN_VMALLOC=y
CONFIG_CC_HAS_KASAN_GENERIC=y
CONFIG_CC_HAS_WORKING_NOSANITIZE_ADDRESS=y
# CONFIG_KASAN is not set
CONFIG_HAVE_ARCH_KFENCE=y
# CONFIG_KFENCE is not set
CONFIG_HAVE_ARCH_KMSAN=y
# end of Memory Debugging

#
# Debug Oops, Lockups and Hangs
#
# CONFIG_PANIC_ON_OOPS is not set
CONFIG_PANIC_ON_OOPS_VALUE=0
CONFIG_PANIC_TIMEOUT=0
CONFIG_HARDLOCKUP_CHECK_TIMESTAMP=y
# end of Debug Oops, Lockups and Hangs

#
# Scheduler Debugging
#
# end of Scheduler Debugging

# CONFIG_DEBUG_TIMEKEEPING is not set

#
# Lock Debugging (spinlocks, mutexes, etc...)
#
CONFIG_LOCK_DEBUGGING_SUPPORT=y
# CONFIG_WW_MUTEX_SELFTEST is not set
# end of Lock Debugging (spinlocks, mutexes, etc...)

# CONFIG_DEBUG_IRQFLAGS is not set
CONFIG_STACKTRACE=y
# CONFIG_WARN_ALL_UNSEEDED_RANDOM is not set

#
# Debug kernel data structures
#
# CONFIG_BUG_ON_DATA_CORRUPTION is not set
# end of Debug kernel data structures

#
# RCU Debugging
#
# end of RCU Debugging

CONFIG_USER_STACKTRACE_SUPPORT=y
CONFIG_HAVE_RETHOOK=y
CONFIG_HAVE_FUNCTION_TRACER=y
CONFIG_HAVE_DYNAMIC_FTRACE=y
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS=y
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS=y
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y
CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE=y
CONFIG_HAVE_FTRACE_MCOUNT_RECORD=y
CONFIG_HAVE_SYSCALL_TRACEPOINTS=y
CONFIG_HAVE_FENTRY=y
CONFIG_HAVE_OBJTOOL_MCOUNT=y
CONFIG_HAVE_C_RECORDMCOUNT=y
CONFIG_HAVE_BUILDTIME_MCOUNT_SORT=y
CONFIG_TRACING_SUPPORT=y
# CONFIG_FTRACE is not set
# CONFIG_SAMPLES is not set
CONFIG_HAVE_SAMPLE_FTRACE_DIRECT=y
CONFIG_HAVE_SAMPLE_FTRACE_DIRECT_MULTI=y
CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y

#
# x86 Debugging
#
# CONFIG_X86_VERBOSE_BOOTUP is not set
CONFIG_EARLY_PRINTK=y
CONFIG_HAVE_MMIOTRACE_SUPPORT=y
CONFIG_IO_DELAY_0X80=y
# CONFIG_IO_DELAY_0XED is not set
# CONFIG_IO_DELAY_UDELAY is not set
# CONFIG_IO_DELAY_NONE is not set
CONFIG_UNWINDER_ORC=y
# CONFIG_UNWINDER_FRAME_POINTER is not set
# end of x86 Debugging

#
# Kernel Testing and Coverage
#
# CONFIG_KUNIT is not set
CONFIG_ARCH_HAS_KCOV=y
CONFIG_CC_HAS_SANCOV_TRACE_PC=y
# CONFIG_KCOV is not set
# CONFIG_RUNTIME_TESTING_MENU is not set
CONFIG_ARCH_USE_MEMTEST=y
# CONFIG_MEMTEST is not set
# end of Kernel Testing and Coverage

#
# Rust hacking
#
# end of Rust hacking

CONFIG_WARN_MISSING_DOCUMENTS=y
CONFIG_WARN_ABI_ERRORS=y
# end of Kernel hacking

Re: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[Leizhen (ThunderTown)]

On 2022/11/13 6:52, kernel test robot wrote:
> Hi Zhen,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on paulmck-rcu/dev]
> [also build test WARNING on tip/sched/core linus/master v6.1-rc4 next-20221111]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Zhen-Lei/rcu-Add-RCU-stall-diagnosis-information/20221111-211035
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
> patch link:    https://lore.kernel.org/r/20221111130709.247-6-thunder.leizhen%40huawei.com
> patch subject: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information
> reproduce:
>         # https://github.com/intel-lab-lkp/linux/commit/062a824ff2c71185d19ff8d39fef18fda82e474f
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Zhen-Lei/rcu-Add-RCU-stall-diagnosis-information/20221111-211035
>         git checkout 062a824ff2c71185d19ff8d39fef18fda82e474f
>         make menuconfig
>         # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
>         make htmldocs
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<------------first timeout---------->|<-----second timeout----->".
>>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<--half timeout-->|<--half timeout-->".
>>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<--first period-->".
>>> Documentation/RCU/stallwarn.rst:415: WARNING: Undefined substitution referenced: "<-----------second sampling period---------->".

Well, thanks. Replacing '|' with ":' solves the problem. Fortunately, they look alike.

> 
> vim +415 Documentation/RCU/stallwarn.rst
> 
>    414	
>  > 415	The sampling period is shown as follows:
>    416	|<------------first timeout---------->|<-----second timeout----->|
>    417	|<--half timeout-->|<--half timeout-->|                          |
>    418	|                  |<--first period-->|                          |
>    419	|                  |<-----------second sampling period---------->|
>    420	|                  |                  |                          |
>    421	|          sampling time point    1st-stall                  2nd-stall
>    422	
>    423	
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[Frederic Weisbecker]

On Fri, Nov 11, 2022 at 09:07:08PM +0800, Zhen Lei wrote:
> +1. A CPU looping with interrupts disabled.::
> +
> +   rcu:          hardirqs   softirqs   csw/system
> +   rcu:  number:        0          0            0
> +65;6003;1c   rcu: cputime:        0          0            0   ==> 2500(ms)
> +
> +   Because interrupts have been disabled throughout the measurement
> +   interval, there are no interrupts and no context switches.
> +   Furthermore, because CPU time consumption was measured using interrupt
> +   handlers, the system CPU consumption is misleadingly measured as zero.
> +   This scenario will normally also have "(0 ticks this GP)" printed on
> +   this CPU's summary line.
> +
> +2. A CPU looping with bottom halves disabled.
> +
> +   This is similar to the previous example, but with non-zero number of
> +   and CPU time consumed by hard interrupts, along with non-zero CPU
> +   time consumed by in-kernel execution.::
> +
> +   rcu:          hardirqs   softirqs   csw/system
> +   rcu:  number:      624          0            0
> +   rcu: cputime:       49          0         2446   ==> 2500(ms)
> +
> +   The fact that there are zero softirqs gives a hint that these were
> +   disabled, perhaps via local_bh_disable().  It is of course possible
> +   that there were no softirqs, perhaps because all events that would
> +   result in softirq execution are confined to other CPUs.  In this case,
> +   the diagnosis should continue as shown in the next example.
> +
> +3. A CPU looping with preemption disabled.
> +
> +   Here, only the number of context switches is zero.::
> +
> +   rcu:          hardirqs   softirqs   csw/system
> +   rcu:  number:      624         45            0
> +   rcu: cputime:       69          1         2425   ==> 2500(ms)
> +
> +   This situation hints that the stalled CPU was looping with preemption
> +   disabled.
> +
> +4. No looping, but massive hard and soft interrupts.::
> +
> +   rcu:          hardirqs   softirqs   csw/system
> +   rcu:  number:       xx         xx            0
> +   rcu: cputime:       xx         xx            0   ==> 2500(ms)
> +
> +   Here, the number and CPU time of hard interrupts are all non-zero,
> +   but the number of context switches and the in-kernel CPU time consumed
> +   are zero. The number and cputime of soft interrupts will usually be
> +   non-zero, but could be zero, for example, if the CPU was spinning
> +   within a single hard interrupt handler.
> +
> +   If this type of RCU CPU stall warning can be reproduced, you can
> +   narrow it down by looking at /proc/interrupts or by writing code to
> +   trace each interrupt, for example, by referring to show_interrupts().

One last question I have. Usually all these informations can be deduced by
just looking at the stacktrace that comes along an RCU stall report. So on
which kind of situation the stacktrace is not enough?

Thanks.

Re: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[Leizhen (ThunderTown)]

On 2022/11/17 6:55, Frederic Weisbecker wrote:
> On Fri, Nov 11, 2022 at 09:07:08PM +0800, Zhen Lei wrote:
>> +1. A CPU looping with interrupts disabled.::
>> +
>> +   rcu:          hardirqs   softirqs   csw/system
>> +   rcu:  number:        0          0            0
>> +65;6003;1c   rcu: cputime:        0          0            0   ==> 2500(ms)
>> +
>> +   Because interrupts have been disabled throughout the measurement
>> +   interval, there are no interrupts and no context switches.
>> +   Furthermore, because CPU time consumption was measured using interrupt
>> +   handlers, the system CPU consumption is misleadingly measured as zero.
>> +   This scenario will normally also have "(0 ticks this GP)" printed on
>> +   this CPU's summary line.
>> +
>> +2. A CPU looping with bottom halves disabled.
>> +
>> +   This is similar to the previous example, but with non-zero number of
>> +   and CPU time consumed by hard interrupts, along with non-zero CPU
>> +   time consumed by in-kernel execution.::
>> +
>> +   rcu:          hardirqs   softirqs   csw/system
>> +   rcu:  number:      624          0            0
>> +   rcu: cputime:       49          0         2446   ==> 2500(ms)
>> +
>> +   The fact that there are zero softirqs gives a hint that these were
>> +   disabled, perhaps via local_bh_disable().  It is of course possible
>> +   that there were no softirqs, perhaps because all events that would
>> +   result in softirq execution are confined to other CPUs.  In this case,
>> +   the diagnosis should continue as shown in the next example.
>> +
>> +3. A CPU looping with preemption disabled.
>> +
>> +   Here, only the number of context switches is zero.::
>> +
>> +   rcu:          hardirqs   softirqs   csw/system
>> +   rcu:  number:      624         45            0
>> +   rcu: cputime:       69          1         2425   ==> 2500(ms)
>> +
>> +   This situation hints that the stalled CPU was looping with preemption
>> +   disabled.
>> +
>> +4. No looping, but massive hard and soft interrupts.::
>> +
>> +   rcu:          hardirqs   softirqs   csw/system
>> +   rcu:  number:       xx         xx            0
>> +   rcu: cputime:       xx         xx            0   ==> 2500(ms)
>> +
>> +   Here, the number and CPU time of hard interrupts are all non-zero,
>> +   but the number of context switches and the in-kernel CPU time consumed
>> +   are zero. The number and cputime of soft interrupts will usually be
>> +   non-zero, but could be zero, for example, if the CPU was spinning
>> +   within a single hard interrupt handler.
>> +
>> +   If this type of RCU CPU stall warning can be reproduced, you can
>> +   narrow it down by looking at /proc/interrupts or by writing code to
>> +   trace each interrupt, for example, by referring to show_interrupts().
> 
> One last question I have. Usually all these informations can be deduced by
> just looking at the stacktrace that comes along an RCU stall report. So on
> which kind of situation the stacktrace is not enough?

Interrupt storm.

> 
> Thanks.
> .
> 

-- 
Regards,
  Zhen Lei

Re: [PATCH v7 5/6] doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information

[Frederic Weisbecker]

On Thu, Nov 17, 2022 at 10:03:17AM +0800, Leizhen (ThunderTown) wrote:
> On 2022/11/17 6:55, Frederic Weisbecker wrote:
> > On Fri, Nov 11, 2022 at 09:07:08PM +0800, Zhen Lei wrote:
> > One last question I have. Usually all these informations can be deduced by
> > just looking at the stacktrace that comes along an RCU stall report. So on
> > which kind of situation the stacktrace is not enough?
> 
> Interrupt storm.

Now that makes sense :)

Thanks.

> 
> > 
> > Thanks.
> > .
> > 
> 
> -- 
> Regards,
>   Zhen Lei

[PATCH v7 6/6] rcu: Align the output of RCU stall

[Zhen Lei]

The time stamps is added to the output when CONFIG_PRINTK_TIME=y, which
will cause the alignment function to fail. So replace pr_cont() with
pr_err(), which also decouples the printing of subfunctions.

Before:
[   37.567343] rcu: INFO: rcu_preempt self-detected stall on CPU
[   37.567839] rcu:     0-....: (1500 ticks this GP) idle=***
[   37.568270]  (t=1501 jiffies g=4717 q=28 ncpus=4)
[   37.568668] CPU: 0 PID: 313 Comm: test0 Not tainted 6.1.0-rc4 #8

After:
[   36.762074] rcu: INFO: rcu_preempt self-detected stall on CPU
[   36.762543] rcu:     0-....: (1499 ticks this GP) idle=***
[   36.763003] rcu:     (t=1500 jiffies g=5097 q=27 ncpus=4)
[   36.763522] CPU: 0 PID: 313 Comm: test0 Not tainted 6.1.0-rc4 #9

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 kernel/rcu/tree_stall.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index a91e844872e59d2..9dc76ba28d372e9 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -619,7 +619,7 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 
 	for_each_possible_cpu(cpu)
 		totqlen += rcu_get_n_cbs_cpu(cpu);
-	pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)\n",
+	pr_err("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)\n",
 	       smp_processor_id(), (long)(jiffies - gps),
 	       (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
 	if (ndetected) {
@@ -680,7 +680,7 @@ static void print_cpu_stall(unsigned long gps)
 	raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags);
 	for_each_possible_cpu(cpu)
 		totqlen += rcu_get_n_cbs_cpu(cpu);
-	pr_cont("\t(t=%lu jiffies g=%ld q=%lu ncpus=%d)\n",
+	pr_err("\t(t=%lu jiffies g=%ld q=%lu ncpus=%d)\n",
 		jiffies - gps,
 		(long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
 
-- 
2.25.1