| Message ID | 20180113170149.22365-4-colyli@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c index 6cc6c0f9c3a9..458e1d38577d 100644 --- a/drivers/md/bcache/alloc.c +++ b/drivers/md/bcache/alloc.c @@ -287,8 +287,10 @@ do { \ break; \ \ mutex_unlock(&(ca)->set->bucket_lock); \ - if (kthread_should_stop()) \ + if (kthread_should_stop()) { \ + set_current_state(TASK_RUNNING); \ return 0; \ + } \ \ schedule(); \ mutex_lock(&(ca)->set->bucket_lock); \
Kernel thread routine bch_allocator_thread() references macro allocator_wait() to wait for a condition or quit to do_exit() when kthread_should_stop() is true. Here is the code block, 284 while (1) { \ 285 set_current_state(TASK_INTERRUPTIBLE); \ 286 if (cond) \ 287 break; \ 288 \ 289 mutex_unlock(&(ca)->set->bucket_lock); \ 290 if (kthread_should_stop()) \ 291 return 0; \ 292 \ 293 schedule(); \ 294 mutex_lock(&(ca)->set->bucket_lock); \ 295 } \ 296 __set_current_state(TASK_RUNNING); \ At line 285, task state is set to TASK_INTERRUPTIBLE, if at line 290 kthread_should_stop() is true, the kernel thread will terminate and return to kernel/kthread.s:kthread(), then calls do_exit() with TASK_INTERRUPTIBLE state. This is not a suggested behavior and a warning message will be reported by might_sleep() in do_exit() code path: "WARNING: do not call blocking ops when !TASK_RUNNING; state=1 set at [xxxx]". This patch fixes this problem by setting task state to TASK_RUNNING if kthread_should_stop() is true and before kernel thread returns back to kernel/kthread.s:kthread(). Changelog: v2: fix the race issue in v1 patch. v1: initial buggy fix. Signed-off-by: Coly Li <colyli@suse.de> Cc: Michael Lyle <mlyle@lyle.org> Cc: Hannes Reinecke <hare@suse.de> Cc: Junhui Tang <tang.junhui@zte.com.cn> --- drivers/md/bcache/alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)