From 550acb19269d65f32e9ac4ddb26c2b2070e37f1c Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Thu, 1 Dec 2011 13:55:08 +0200 Subject: [PATCH 1/2] genirq: Fix race condition when stopping the irq thread In irq_wait_for_interrupt(), the should_stop member is verified before setting the task's state to TASK_INTERRUPTIBLE and calling schedule(). In case kthread_stop sets should_stop and wakes up the process after should_stop is checked by the irq thread but before the task's state is changed, the irq thread might never exit: kthread_stop irq_wait_for_interrupt ------------ ---------------------- ... ... while (!kthread_should_stop()) { kthread->should_stop = 1; wake_up_process(k); wait_for_completion(&kthread->exited); ... set_current_state(TASK_INTERRUPTIBLE); ... schedule(); } Fix this by checking if the thread should stop after modifying the task's state. [ tglx: Simplified it a bit ] Signed-off-by: Ido Yariv Link: http://lkml.kernel.org/r/1322740508-22640-1-git-send-email-ido@wizery.com Signed-off-by: Thomas Gleixner Cc: stable@kernel.org --- kernel/irq/manage.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0e2b179bc7b3..1da999f5e746 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -623,8 +623,9 @@ static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id) static int irq_wait_for_interrupt(struct irqaction *action) { + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { - set_current_state(TASK_INTERRUPTIBLE); if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) { @@ -632,7 +633,9 @@ static int irq_wait_for_interrupt(struct irqaction *action) return 0; } schedule(); + set_current_state(TASK_INTERRUPTIBLE); } + __set_current_state(TASK_RUNNING); return -1; } From 52cef189165d74a5d6030184a8e05595194c69ca Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 28 Nov 2011 21:12:40 +0100 Subject: [PATCH 2/2] slab, lockdep: Fix silly bug Commit 30765b92 ("slab, lockdep: Annotate the locks before using them") moves the init_lock_keys() call from after g_cpucache_up = FULL, to before it. And overlooks the fact that init_node_lock_keys() tests for it and ignores everything !FULL. Introduce a LATE stage and change the lockdep test to be Cc: Pekka Enberg Cc: stable@kernel.org Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- mm/slab.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/slab.c b/mm/slab.c index 708efe886154..83311c9aaf9d 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -595,6 +595,7 @@ static enum { PARTIAL_AC, PARTIAL_L3, EARLY, + LATE, FULL } g_cpucache_up; @@ -671,7 +672,7 @@ static void init_node_lock_keys(int q) { struct cache_sizes *s = malloc_sizes; - if (g_cpucache_up != FULL) + if (g_cpucache_up < LATE) return; for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) { @@ -1666,6 +1667,8 @@ void __init kmem_cache_init_late(void) { struct kmem_cache *cachep; + g_cpucache_up = LATE; + /* Annotate slab for lockdep -- annotate the malloc caches */ init_lock_keys();