diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-09-02 14:29:27 +0200 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2011-11-14 11:01:56 -0600 |
| commit | 1e1c91cabd8ac71062ce5e93b4e7ec5dbe094fc2 (patch) | |
| tree | d966024068b05b6de96ef712c2aeeb816b82d889 | |
| parent | bc657abbbb4738478fc5f3522970e31cc809f67a (diff) | |
sched: teach migrate_disable about atomic contexts
<NMI> [<ffffffff812dafd8>] spin_bug+0x94/0xa8
[<ffffffff812db07f>] do_raw_spin_lock+0x43/0xea
[<ffffffff814fa9be>] _raw_spin_lock_irqsave+0x6b/0x85
[<ffffffff8106ff9e>] ? migrate_disable+0x75/0x12d
[<ffffffff81078aaf>] ? pin_current_cpu+0x36/0xb0
[<ffffffff8106ff9e>] migrate_disable+0x75/0x12d
[<ffffffff81115b9d>] pagefault_disable+0xe/0x1f
[<ffffffff81047027>] copy_from_user_nmi+0x74/0xe6
[<ffffffff810489d7>] perf_callchain_user+0xf3/0x135
Now clearly we can't go around taking locks from NMI context, cure
this by short-circuiting migrate_disable() when we're in an atomic
context already.
Add some extra debugging to avoid things like:
preempt_disable()
migrate_disable();
preempt_enable();
migrate_enable();
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1314967297.1301.14.camel@twins
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/n/tip-wbot4vsmwhi8vmbf83hsclk6@git.kernel.org
| -rw-r--r-- | include/linux/sched.h | 3 | ||||
| -rw-r--r-- | kernel/sched.c | 21 |
2 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 1c322efeaba0..562a3451a9a4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1261,6 +1261,9 @@ struct task_struct { unsigned int policy; #ifdef CONFIG_PREEMPT_RT_FULL int migrate_disable; +#ifdef CONFIG_SCHED_DEBUG + int migrate_disable_atomic; +#endif #endif cpumask_t cpus_allowed; diff --git a/kernel/sched.c b/kernel/sched.c index 56ec6c221340..7693fda061f2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6292,6 +6292,17 @@ void migrate_disable(void) unsigned long flags; struct rq *rq; + if (in_atomic()) { +#ifdef CONFIG_SCHED_DEBUG + p->migrate_disable_atomic++; +#endif + return; + } + +#ifdef CONFIG_SCHED_DEBUG + WARN_ON_ONCE(p->migrate_disable_atomic); +#endif + preempt_disable(); if (p->migrate_disable) { p->migrate_disable++; @@ -6340,6 +6351,16 @@ void migrate_enable(void) unsigned long flags; struct rq *rq; + if (in_atomic()) { +#ifdef CONFIG_SCHED_DEBUG + p->migrate_disable_atomic--; +#endif + return; + } + +#ifdef CONFIG_SCHED_DEBUG + WARN_ON_ONCE(p->migrate_disable_atomic); +#endif WARN_ON_ONCE(p->migrate_disable <= 0); preempt_disable(); |