[PATCH RT 0/7] Linux 3.2.77-rt112-rc1

[PATCH RT 0/7] Linux 3.2.77-rt112-rc1

[Steven Rostedt]

Dear RT Folks,

This is the RT stable review cycle of patch 3.2.77-rt112-rc1.

Please scream at me if I messed something up. Please test the patches too.

The -rc release will be uploaded to kernel.org and will be deleted when
the final release is out. This is just a review release (or release candidate).

The pre-releases will not be pushed to the git repository, only the
final release is.

If all goes well, this patch will be converted to the next main release
on 3/7/2016.

Enjoy,

-- Steve


To build 3.2.77-rt112-rc1 directly, the following patches should be applied:

  http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.2.tar.xz

  http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.2.77.xz

  http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/patch-3.2.77-rt112-rc1.patch.xz

You can also build from 3.2.77-rt111 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/incr/patch-3.2.77-rt111-rt112-rc1.patch.xz


Changes from 3.2.77-rt111:

---


Clark Williams (1):
      rcu/torture: Comment out rcu_bh ops on PREEMPT_RT_FULL

Sebastian Andrzej Siewior (4):
      latencyhist: disable jump-labels
      kernel: migrate_disable() do fastpath in atomic & irqs-off
      kernel: softirq: unlock with irqs on
      kernel: sched: Fix preempt_disable_ip recodring for preempt_disable()

Steven Rostedt (Red Hat) (1):
      Linux 3.2.77-rt112-rc1

Yang Shi (1):
      trace: Use rcuidle version for preemptoff_hist trace point

----
 arch/Kconfig                 |  1 +
 include/linux/ftrace.h       | 12 ++++++++++++
 include/linux/sched.h        |  2 --
 include/trace/events/hist.h  |  1 +
 kernel/rcutorture.c          |  7 +++++++
 kernel/sched.c               | 18 ++++--------------
 kernel/softirq.c             |  6 +++---
 kernel/trace/trace_irqsoff.c |  8 ++++----
 localversion-rt              |  2 +-
 9 files changed, 33 insertions(+), 24 deletions(-)

[PATCH RT 1/7] latencyhist: disable jump-labels

[Steven Rostedt]

[-- Attachment #1: 0001-latencyhist-disable-jump-labels.patch --]
[-- Type: text/plain, Size: 2905 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Atleast on X86 we die a recursive death

|CPU: 3 PID: 585 Comm: bash Not tainted 4.4.1-rt4+ #198
|Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Debian-1.8.2-1 04/01/2014
|task: ffff88007ab4cd00 ti: ffff88007ab94000 task.ti: ffff88007ab94000
|RIP: 0010:[<ffffffff81684870>]  [<ffffffff81684870>] int3+0x0/0x10
|RSP: 0018:ffff88013c107fd8  EFLAGS: 00010082
|RAX: ffff88007ab4cd00 RBX: ffffffff8100ceab RCX: 0000000080202001
|RDX: 0000000000000000 RSI: ffffffff8100ceab RDI: ffffffff810c78b2
|RBP: ffff88007ab97c10 R08: ffffffffff57b000 R09: 0000000000000000
|R10: ffff88013bb64790 R11: ffff88007ab4cd68 R12: ffffffff8100ceab
|R13: ffffffff810c78b2 R14: ffffffff810f8158 R15: ffffffff810f9120
|FS:  0000000000000000(0000) GS:ffff88013c100000(0063) knlGS:00000000f74e3940
|CS:  0010 DS: 002b ES: 002b CR0: 000000008005003b
|CR2: 0000000008cf6008 CR3: 000000013b169000 CR4: 00000000000006e0
|Call Trace:
| <#DB>
| [<ffffffff810f8158>] ? trace_preempt_off+0x18/0x170
| <<EOE>>
| [<ffffffff81077745>] preempt_count_add+0xa5/0xc0
| [<ffffffff810c78b2>] on_each_cpu+0x22/0x90
| [<ffffffff8100ceab>] text_poke_bp+0x5b/0xc0
| [<ffffffff8100a29c>] arch_jump_label_transform+0x8c/0xf0
| [<ffffffff8111c77c>] __jump_label_update+0x6c/0x80
| [<ffffffff8111c83a>] jump_label_update+0xaa/0xc0
| [<ffffffff8111ca54>] static_key_slow_inc+0x94/0xa0
| [<ffffffff810e0d8d>] tracepoint_probe_register_prio+0x26d/0x2c0
| [<ffffffff810e0df3>] tracepoint_probe_register+0x13/0x20
| [<ffffffff810fca78>] trace_event_reg+0x98/0xd0
| [<ffffffff810fcc8b>] __ftrace_event_enable_disable+0x6b/0x180
| [<ffffffff810fd5b8>] event_enable_write+0x78/0xc0
| [<ffffffff8117a768>] __vfs_write+0x28/0xe0
| [<ffffffff8117b025>] vfs_write+0xa5/0x180
| [<ffffffff8117bb76>] SyS_write+0x46/0xa0
| [<ffffffff81002c91>] do_fast_syscall_32+0xa1/0x1d0
| [<ffffffff81684d57>] sysenter_flags_fixed+0xd/0x17

during
 echo 1 > /sys/kernel/debug/tracing/events/hist/preemptirqsoff_hist/enable

Reported-By: Christoph Mathys <eraserix@gmail.com>
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index 73fc7cd51582..5e921bd9a57b 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -46,6 +46,7 @@ config KPROBES
 config JUMP_LABEL
        bool "Optimize trace point call sites"
        depends on HAVE_ARCH_JUMP_LABEL
+       depends on (!INTERRUPT_OFF_HIST && !PREEMPT_OFF_HIST && !WAKEUP_LATENCY_HIST && !MISSED_TIMER_OFFSETS_HIST)
        help
          If it is detected that the compiler has support for "asm goto",
 	 the kernel will compile trace point locations with just a
-- 
2.7.0

[PATCH RT 2/7] kernel: migrate_disable() do fastpath in atomic & irqs-off

[Steven Rostedt]

[-- Attachment #1: 0002-kernel-migrate_disable-do-fastpath-in-atomic-irqs-of.patch --]
[-- Type: text/plain, Size: 1082 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

With interrupts off it makes no sense to do the long path since we can't
leave the CPU anyway. Also we might end up in a recursion with lockdep.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/sched.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index a9f6d6c0ab93..24d7256ce0b2 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4611,7 +4611,7 @@ void migrate_disable(void)
 {
 	struct task_struct *p = current;
 
-	if (in_atomic()) {
+	if (in_atomic() || irqs_disabled()) {
 #ifdef CONFIG_SCHED_DEBUG
 		p->migrate_disable_atomic++;
 #endif
@@ -4642,7 +4642,7 @@ void migrate_enable(void)
 	unsigned long flags;
 	struct rq *rq;
 
-	if (in_atomic()) {
+	if (in_atomic() || irqs_disabled()) {
 #ifdef CONFIG_SCHED_DEBUG
 		p->migrate_disable_atomic--;
 #endif
-- 
2.7.0

[PATCH RT 3/7] kernel: softirq: unlock with irqs on

[Steven Rostedt]

[-- Attachment #1: 0003-kernel-softirq-unlock-with-irqs-on.patch --]
[-- Type: text/plain, Size: 1004 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We unlock the lock while the interrupts are off. This isn't a problem
now but will get because the migrate_disable() + enable are not
symmetrical in regard to the status of interrupts.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/softirq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index b7d68392e833..61860daa4098 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -561,10 +561,10 @@ static int __thread_do_softirq(int cpu)
 	 */
 	if (local_softirq_pending())
 		__do_softirq_common(cpu >= 0);
-	local_unlock(local_softirq_lock);
 	unpin_current_cpu();
-	preempt_disable();
 	local_irq_enable();
+	local_unlock(local_softirq_lock);
+	preempt_disable();
 	return 0;
 }
 
-- 
2.7.0

[PATCH RT 4/7] trace: Use rcuidle version for preemptoff_hist trace point

[Steven Rostedt]

[-- Attachment #1: 0004-trace-Use-rcuidle-version-for-preemptoff_hist-trace-.patch --]
[-- Type: text/plain, Size: 3972 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Yang Shi <yang.shi@windriver.com>

When running -rt kernel with both PREEMPT_OFF_HIST and LOCKDEP enabled,
the below error is reported:

 [ INFO: suspicious RCU usage. ]
 4.4.1-rt6 #1 Not tainted
 include/trace/events/hist.h:31 suspicious rcu_dereference_check() usage!

 other info that might help us debug this:

 RCU used illegally from idle CPU!
 rcu_scheduler_active = 1, debug_locks = 0
 RCU used illegally from extended quiescent state!
 no locks held by swapper/0/0.

 stack backtrace:
 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.1-rt6-WR8.0.0.0_standard #1
 Stack : 0000000000000006 0000000000000000 ffffffff81ca8c38 ffffffff81c8fc80
    ffffffff811bdd68 ffffffff81cb0000 0000000000000000 ffffffff81cb0000
    0000000000000000 0000000000000000 0000000000000004 0000000000000000
    0000000000000004 ffffffff811bdf50 0000000000000000 ffffffff82b60000
    0000000000000000 ffffffff812897ac ffffffff819f0000 000000000000000b
    ffffffff811be460 ffffffff81b7c588 ffffffff81c8fc80 0000000000000000
    0000000000000000 ffffffff81ec7f88 ffffffff81d70000 ffffffff81b70000
    ffffffff81c90000 ffffffff81c3fb00 ffffffff81c3fc28 ffffffff815e6f98
    0000000000000000 ffffffff81c8fa87 ffffffff81b70958 ffffffff811bf2c4
    0707fe32e8d60ca5 ffffffff81126d60 0000000000000000 0000000000000000
    ...
 Call Trace:
 [<ffffffff81126d60>] show_stack+0xe8/0x108
 [<ffffffff815e6f98>] dump_stack+0x88/0xb0
 [<ffffffff8124b88c>] time_hardirqs_off+0x204/0x300
 [<ffffffff811aa5dc>] trace_hardirqs_off_caller+0x24/0xe8
 [<ffffffff811a4ec4>] cpu_startup_entry+0x39c/0x508
 [<ffffffff81d7dc68>] start_kernel+0x584/0x5a0

Replace regular trace_preemptoff_hist to rcuidle version to avoid the error.

Signed-off-by: Yang Shi <yang.shi@windriver.com>
Cc: bigeasy@linutronix.de
Cc: rostedt@goodmis.org
Cc: linux-rt-users@vger.kernel.org
Link: http://lkml.kernel.org/r/1456262603-10075-1-git-send-email-yang.shi@windriver.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/trace/events/hist.h  | 1 +
 kernel/trace/trace_irqsoff.c | 8 ++++----
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/trace/events/hist.h b/include/trace/events/hist.h
index 28646db2c775..47332b93e03d 100644
--- a/include/trace/events/hist.h
+++ b/include/trace/events/hist.h
@@ -9,6 +9,7 @@
 
 #if !defined(CONFIG_PREEMPT_OFF_HIST) && !defined(CONFIG_INTERRUPT_OFF_HIST)
 #define trace_preemptirqsoff_hist(a,b)
+#define trace_preemptirqsoff_hist_rcuidle(a, b)
 #else
 TRACE_EVENT(preemptirqsoff_hist,
 
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 35882e792c2f..9e351280434a 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -427,13 +427,13 @@ void start_critical_timings(void)
 {
 	if (preempt_trace() || irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-	trace_preemptirqsoff_hist(TRACE_START, 1);
+	trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1);
 }
 EXPORT_SYMBOL_GPL(start_critical_timings);
 
 void stop_critical_timings(void)
 {
-	trace_preemptirqsoff_hist(TRACE_STOP, 0);
+	trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0);
 	if (preempt_trace() || irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
@@ -478,7 +478,7 @@ inline void print_irqtrace_events(struct task_struct *curr)
  */
 void trace_hardirqs_on(void)
 {
-	trace_preemptirqsoff_hist(IRQS_ON, 0);
+	trace_preemptirqsoff_hist_rcuidle(IRQS_ON, 0);
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
@@ -488,7 +488,7 @@ void trace_hardirqs_off(void)
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
-	trace_preemptirqsoff_hist(IRQS_OFF, 1);
+	trace_preemptirqsoff_hist_rcuidle(IRQS_OFF, 1);
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 
-- 
2.7.0

[PATCH RT 5/7] rcu/torture: Comment out rcu_bh ops on PREEMPT_RT_FULL

[Steven Rostedt]

[-- Attachment #1: 0005-rcu-torture-Comment-out-rcu_bh-ops-on-PREEMPT_RT_FUL.patch --]
[-- Type: text/plain, Size: 1116 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Clark Williams <williams@redhat.com>

RT has dropped support of rcu_bh, comment out in rcutorture.

Signed-off-by: Clark Williams <williams@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/rcutorture.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 764825c2685c..3cd7834c7da6 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -455,6 +455,7 @@ static struct rcu_torture_ops rcu_expedited_ops = {
 	.name		= "rcu_expedited"
 };
 
+#ifndef CONFIG_PREEMPT_RT_FULL
 /*
  * Definitions for rcu_bh torture testing.
  */
@@ -528,6 +529,12 @@ static struct rcu_torture_ops rcu_bh_expedited_ops = {
 	.name		= "rcu_bh_expedited"
 };
 
+#else
+static struct rcu_torture_ops rcu_bh_ops = {
+	.ttype		= INVALID_RCU_FLAVOR,
+};
+#endif
+
 /*
  * Definitions for srcu torture testing.
  */
-- 
2.7.0

[PATCH RT 6/7] kernel: sched: Fix preempt_disable_ip recodring for preempt_disable()

[Steven Rostedt]

[-- Attachment #1: 0006-kernel-sched-Fix-preempt_disable_ip-recodring-for-pr.patch --]
[-- Type: text/plain, Size: 3863 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

preempt_disable() invokes preempt_count_add() which saves the caller in
current->preempt_disable_ip. It uses CALLER_ADDR1 which does not look for its
caller but for the parent of the caller. Which means we get the correct caller
for something like spin_lock() unless the architectures inlines those
invocations. It is always wrong for preempt_disable() or local_bh_disable().

This patch makes the function get_parent_ip() which tries CALLER_ADDR0,1,2 if
the former is a locking function.  This seems to record the preempt_disable()
caller properly for preempt_disable() itself as well as for get_cpu_var() or
local_bh_disable().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace.h | 12 ++++++++++++
 include/linux/sched.h  |  2 --
 kernel/sched.c         | 14 ++------------
 kernel/softirq.c       |  2 +-
 4 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index a3ebb09d4283..3c87797e371e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -341,6 +341,18 @@ static inline void __ftrace_enabled_restore(int enabled)
 # endif
 #endif /* ifndef HAVE_ARCH_CALLER_ADDR */
 
+static inline unsigned long get_lock_parent_ip(void)
+{
+	unsigned long addr = CALLER_ADDR0;
+
+	if (!in_lock_functions(addr))
+		return addr;
+	addr = CALLER_ADDR1;
+	if (!in_lock_functions(addr))
+		return addr;
+	return CALLER_ADDR2;
+}
+
 #ifdef CONFIG_IRQSOFF_TRACER
   extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
   extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a15cfd1bac9f..3cb870f1ffc1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -149,8 +149,6 @@ extern unsigned long this_cpu_load(void);
 extern void calc_global_load(unsigned long ticks);
 extern void update_cpu_load_nohz(void);
 
-extern unsigned long get_parent_ip(unsigned long addr);
-
 struct seq_file;
 struct cfs_rq;
 struct task_group;
diff --git a/kernel/sched.c b/kernel/sched.c
index 24d7256ce0b2..abc27a937c1b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4460,16 +4460,6 @@ void scheduler_tick(void)
 #endif
 }
 
-notrace unsigned long get_parent_ip(unsigned long addr)
-{
-	if (in_lock_functions(addr)) {
-		addr = CALLER_ADDR2;
-		if (in_lock_functions(addr))
-			addr = CALLER_ADDR3;
-	}
-	return addr;
-}
-
 #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
 				defined(CONFIG_PREEMPT_TRACER))
 
@@ -4491,7 +4481,7 @@ void __kprobes add_preempt_count(int val)
 				PREEMPT_MASK - 10);
 #endif
 	if (preempt_count() == val) {
-		unsigned long ip = get_parent_ip(CALLER_ADDR1);
+		unsigned long ip = get_lock_parent_ip();
 #ifdef CONFIG_DEBUG_PREEMPT
 		current->preempt_disable_ip = ip;
 #endif
@@ -4517,7 +4507,7 @@ void __kprobes sub_preempt_count(int val)
 #endif
 
 	if (preempt_count() == val)
-		trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
 	preempt_count() -= val;
 }
 EXPORT_SYMBOL(sub_preempt_count);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 61860daa4098..b03c01c77d92 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -207,7 +207,7 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
 	raw_local_irq_restore(flags);
 
 	if (preempt_count() == cnt)
-		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
+		trace_preempt_off(CALLER_ADDR0, get_lock_parent_ip());
 }
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip, unsigned int cnt)
-- 
2.7.0

[PATCH RT 7/7] Linux 3.2.77-rt112-rc1

[Steven Rostedt]

[-- Attachment #1: 0007-Linux-3.2.77-rt112-rc1.patch --]
[-- Type: text/plain, Size: 414 bytes --]

3.2.77-rt112-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

---
 localversion-rt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/localversion-rt b/localversion-rt
index 9969a4b69fad..80c07f1b2fd7 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt111
+-rt112-rc1
-- 
2.7.0