commit: 1eda5166c7640092f512138be6899d050c3d62ed From: Paul E. McKenney <[email protected]> Date: Wed, 7 Mar 2012 17:54:00 +0400 Subject: staging: android/lowmemorykiller: Don't unregister notifier from atomic context
The lowmemorykiller registers an atomic notifier for notfication of when the task is freed. From this atomic notifier callback, it removes the atomic notifier via task_free_unregister(). This is incorrect because atomic_notifier_chain_unregister() calls syncronize_rcu(), which can sleep, which shouldn't be done from an atomic notifier. Fix this by registering the notifier during init, and only unregister it if the lowmemorykiller is unloaded. Rebased to -next by Paul E. McKenney. Rebased to -next again by Anton Vorontsov. Signed-off-by: Rabin Vincent <[email protected]> Signed-off-by: Christian Bejram <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> Reported-by: John Stultz <[email protected]> Signed-off-by: Anton Vorontsov <[email protected]> Cc: stable <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/staging/android/lowmemorykiller.c | 14 +++++++------- 1 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c index cf4c6f7..03d1de2 100644 --- a/drivers/staging/android/lowmemorykiller.c +++ b/drivers/staging/android/lowmemorykiller.c @@ -75,10 +75,10 @@ static int task_notify_func(struct notifier_block *self, unsigned long val, void *data) { struct task_struct *task = data; - if (task == lowmem_deathpending) { + + if (task == lowmem_deathpending) lowmem_deathpending = NULL; - task_handoff_unregister(&task_nb); - } + return NOTIFY_OK; } @@ -175,14 +175,12 @@ static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc) selected->pid, selected->comm, selected_oom_score_adj, selected_tasksize); /* - * If CONFIG_PROFILING is off, then task_handoff_register() - * is a nop. In that case we don't want to stall the killer - * by setting lowmem_deathpending. + * If CONFIG_PROFILING is off, then we don't want to stall + * the killer by setting lowmem_deathpending. */ #ifdef CONFIG_PROFILING lowmem_deathpending = selected; lowmem_deathpending_timeout = jiffies + HZ; - task_handoff_register(&task_nb); #endif send_sig(SIGKILL, selected, 0); rem -= selected_tasksize; @@ -200,6 +198,7 @@ static struct shrinker lowmem_shrinker = { static int __init lowmem_init(void) { + task_handoff_register(&task_nb); register_shrinker(&lowmem_shrinker); return 0; } @@ -207,6 +206,7 @@ static int __init lowmem_init(void) static void __exit lowmem_exit(void) { unregister_shrinker(&lowmem_shrinker); + task_handoff_unregister(&task_nb); } module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
