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authorSteven Rostedt <rostedt@goodmis.org>2014-05-27 17:02:04 -0400
committerIngo Molnar <mingo@kernel.org>2014-06-05 11:07:41 +0200
commite9dd685ce81815811fb4da72e6ab10a694ac8468 (patch)
treec429c73cf5883cf54aef8b07c71b212c1c708071 /kernel/sched
parent6acbfb96976fc3350e30d964acb1dbbdf876d55e (diff)
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.c7
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);
}