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| author | Steven Rostedt <rostedt@goodmis.org> | 2014-05-27 17:02:04 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-06-05 11:07:41 +0200 |
| commit | e9dd685ce81815811fb4da72e6ab10a694ac8468 (patch) | |
| tree | c429c73cf5883cf54aef8b07c71b212c1c708071 /kernel/sched | |
| parent | 6acbfb96976fc3350e30d964acb1dbbdf876d55e (diff) | |
| download | lwn-e9dd685ce81815811fb4da72e6ab10a694ac8468.tar.gz lwn-e9dd685ce81815811fb4da72e6ab10a694ac8468.zip | |
sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabled
As Peter Zijlstra told me, we have the following path:
do_exit()
exit_itimers()
itimer_delete()
spin_lock_irqsave(&timer->it_lock, &flags);
timer_delete_hook(timer);
kc->timer_del(timer) := posix_cpu_timer_del()
put_task_struct()
__put_task_struct()
task_numa_free()
spin_lock(&grp->lock);
Which means that task_numa_free() can be called with interrupts
disabled, which means that we should not be using spin_lock_irq() but
spin_lock_irqsave() instead. Otherwise we are enabling interrupts while
holding an interrupt unsafe lock!
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner<tglx@linutronix.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140527182541.GH11096@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0fdb96de81a5..b4768c069392 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1707,18 +1707,19 @@ no_join: void task_numa_free(struct task_struct *p) { struct numa_group *grp = p->numa_group; - int i; void *numa_faults = p->numa_faults_memory; + unsigned long flags; + int i; if (grp) { - spin_lock_irq(&grp->lock); + spin_lock_irqsave(&grp->lock, flags); for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) grp->faults[i] -= p->numa_faults_memory[i]; grp->total_faults -= p->total_numa_faults; list_del(&p->numa_entry); grp->nr_tasks--; - spin_unlock_irq(&grp->lock); + spin_unlock_irqrestore(&grp->lock, flags); rcu_assign_pointer(p->numa_group, NULL); put_numa_group(grp); } |