| Message ID | 20180114144236.28213-4-colyli@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 01/14/2018 03:42 PM, Coly Li wrote: > 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(-) > > 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); \ > Might be an idea to merge it with the previous patch. Other than that: Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
On 16/01/2018 5:05 PM, Hannes Reinecke wrote: > On 01/14/2018 03:42 PM, Coly Li wrote: >> 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(-) >> >> 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); \ >> > Might be an idea to merge it with the previous patch. > > Other than that: > > Reviewed-by: Hannes Reinecke <hare@suse.com> Hi Hannes, Sure, I will do that in v4 patche set. Thanks for the review. Coly Li
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(-)