From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> 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 <rabin.vincent@xxxxxxxxxxxxxx> Signed-off-by: Christian Bejram <christian.bejram@xxxxxxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Reported-by: John Stultz <john.stultz@xxxxxxxxxx> Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> --- This is respin of http://lkml.org/lkml/2012/1/3/265, which does not apply cleanly nowadays. 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); -- 1.7.7.6 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
