From: Chuansheng Liu <chuansheng.liu@intel.com>
To: mingo@kernel.org
Cc: peterz@infradead.org, jbeulich@suse.com,
paulmck@linux.vnet.ibm.com, akpm@linux-foundation.org,
mina86@mina86.org, srivatsa.bhat@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, jun.zhang@intel.com,
fengguang.wu@intel.com, chuansheng.liu@intel.com
Subject: [PATCH V2] smp: Give WARN()ing when calling smp_call_function_many()/single() in serving irq
Date: Sat, 16 Feb 2013 22:10:12 +0800 [thread overview]
Message-ID: <1361023812.11130.15.camel@cliu38-desktop-build> (raw)
In-Reply-To: <1361023075.11130.12.camel@cliu38-desktop-build>
Currently the functions smp_call_function_many()/single() will
give a WARN()ing only in the case of irqs_disabled(), but that
check is not enough to guarantee execution of the SMP
cross-calls.
In many other cases such as softirq handling/interrupt handling,
the two APIs still can not be called, just as the
smp_call_function_many() comments say:
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. Preemption
* must be disabled when calling this function.
There is a real case for softirq DEADLOCK case:
CPUA CPUB
spin_lock(&spinlock)
Any irq coming, call the irq handler
irq_exit()
spin_lock_irq(&spinlock)
<== Blocking here due to
CPUB hold it
__do_softirq()
run_timer_softirq()
timer_cb()
call smp_call_function_many()
send IPI interrupt to CPUA
wait_csd()
Then both CPUA and CPUB will be deadlocked here.
So we should give a warning in the nmi, hardirq or softirq context as well.
Moreover, adding one new macro in_serving_irq() which indicates
we are processing nmi, hardirq or sofirq.
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
---
include/linux/hardirq.h | 5 +++++
kernel/smp.c | 11 +++++++----
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 624ef3f..e07663f 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -94,6 +94,11 @@
*/
#define in_nmi() (preempt_count() & NMI_MASK)
+/*
+ * Are we in nmi,irq context, or softirq context?
+ */
+#define in_serving_irq() (in_nmi() || in_irq() || in_serving_softirq())
+
#if defined(CONFIG_PREEMPT_COUNT)
# define PREEMPT_CHECK_OFFSET 1
#else
diff --git a/kernel/smp.c b/kernel/smp.c
index 69f38bd..b0a5d21 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -12,6 +12,7 @@
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
+#include <linux/hardirq.h>
#include "smpboot.h"
@@ -323,8 +324,9 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
- WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
- && !oops_in_progress);
+ WARN_ON_ONCE(cpu_online(this_cpu)
+ && (irqs_disabled() || in_serving_irq())
+ && !oops_in_progress);
if (cpu == this_cpu) {
local_irq_save(flags);
@@ -462,8 +464,9 @@ void smp_call_function_many(const struct cpumask *mask,
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
- WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
- && !oops_in_progress && !early_boot_irqs_disabled);
+ WARN_ON_ONCE(cpu_online(this_cpu)
+ && (irqs_disabled() || in_serving_irq())
+ && !oops_in_progress && !early_boot_irqs_disabled);
/* Try to fastpath. So, what's a CPU they want? Ignoring this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
--
1.7.0.4
next prev parent reply other threads:[~2013-02-16 5:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-06 15:18 [PATCH] smp: give WARN in case of in_interrupt() when calling smp_call_function_many/single Chuansheng Liu
2013-02-06 13:42 ` [tip:core/locking] smp: Give WARN()ing if in_interrupt() when calling smp_call_function_many()/single() tip-bot for Chuansheng Liu
2013-02-11 12:20 ` [tip:core/locking] Revert "smp: Give WARN()ing if in_interrupt() when calling smp_call_function_many()/single()" tip-bot for Ingo Molnar
2013-02-16 5:26 ` Liu, Chuansheng
2013-02-16 13:57 ` [PATCH] smp: Give WARN()ing when calling smp_call_function_many()/single() in serving irq Chuansheng Liu
2013-02-16 14:10 ` Chuansheng Liu [this message]
2013-02-18 1:38 ` [PATCH V2] " Fengguang Wu
2013-02-19 23:01 ` Andrew Morton
2013-02-20 1:06 ` Fengguang Wu
2013-02-20 1:22 ` Liu, Chuansheng
2013-02-27 14:50 ` Lai Jiangshan
2013-03-01 3:37 ` Liu, Chuansheng
2013-08-05 22:46 ` Andrew Morton
2013-07-05 13:50 ` Thomas Gleixner
2013-07-05 14:37 ` Thomas Gleixner
2013-07-07 3:59 ` Wang YanQing
2013-07-07 13:47 ` Thomas Gleixner
2013-12-06 1:29 ` Max Filippov
2013-12-06 14:02 ` Thomas Gleixner
2013-12-06 18:31 ` Max Filippov
2013-07-07 2:41 ` Wang YanQing
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