From: Hannes Reinecke <hare@suse.de>
To: Coly Li <colyli@suse.de>, linux-bcache@vger.kernel.org
Cc: linux-block@vger.kernel.org, Michael Lyle <mlyle@lyle.org>,
Junhui Tang <tang.junhui@zte.com.cn>
Subject: Re: [PATCH v3 03/13] bcache: set task properly in allocator_wait()
Date: Tue, 16 Jan 2018 10:05:10 +0100 [thread overview]
Message-ID: <5018c875-a48e-98b2-17a6-d1ae3a879c78@suse.de> (raw)
In-Reply-To: <20180114144236.28213-4-colyli@suse.de>
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
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@suse.de +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
next prev parent reply other threads:[~2018-01-16 9:05 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-14 14:42 [PATCH v3 00/13] bcache: device failure handling improvement Coly Li
2018-01-14 14:42 ` [PATCH v3 01/13] bcache: set writeback_rate_update_seconds in range [1, 60] seconds Coly Li
2018-01-16 9:03 ` Hannes Reinecke
2018-01-14 14:42 ` [PATCH v3 02/13] bcache: properly set task state in bch_writeback_thread() Coly Li
2018-01-16 9:02 ` Hannes Reinecke
2018-01-14 14:42 ` [PATCH v3 03/13] bcache: set task properly in allocator_wait() Coly Li
2018-01-16 9:05 ` Hannes Reinecke [this message]
2018-01-16 9:29 ` Coly Li
2018-01-14 14:42 ` [PATCH v3 04/13] bcache: fix cached_dev->count usage for bch_cache_set_error() Coly Li
2018-01-14 14:42 ` [PATCH v3 05/13] bcache: quit dc->writeback_thread when BCACHE_DEV_DETACHING is set Coly Li
2018-01-16 9:11 ` Hannes Reinecke
2018-01-26 6:21 ` Coly Li
2018-01-14 14:42 ` [PATCH v3 06/13] bcache: stop dc->writeback_rate_update properly Coly Li
2018-01-14 14:42 ` [PATCH v3 07/13] bcache: set error_limit correctly Coly Li
2018-01-14 14:42 ` [PATCH v3 08/13] bcache: add CACHE_SET_IO_DISABLE to struct cache_set flags Coly Li
2018-01-14 14:42 ` [PATCH v3 09/13] bcache: stop all attached bcache devices for a retired cache set Coly Li
2018-01-14 14:42 ` [PATCH v3 10/13] bcache: fix inaccurate io state for detached bcache devices Coly Li
2018-01-16 9:27 ` Hannes Reinecke
2018-01-14 14:42 ` [PATCH v3 11/13] bcache: add backing_request_endio() for bi_end_io of attached backing device I/O Coly Li
2018-01-16 9:28 ` Hannes Reinecke
2018-01-14 14:42 ` [PATCH v3 12/13] bcache: add io_disable to struct cached_dev Coly Li
2018-01-16 9:32 ` Hannes Reinecke
2018-01-14 14:42 ` [PATCH v3 13/13] bcache: stop bcache device when backing device is offline Coly Li
2018-01-16 9:33 ` Hannes Reinecke
2018-01-24 22:23 ` [PATCH v3 00/13] bcache: device failure handling improvement Nix
2018-01-25 3:35 ` Re[2]: " Pavel Goran
2018-01-25 18:57 ` Nix
2018-01-26 4:15 ` Re[2]: " Pavel Goran
2018-01-26 4:56 ` Coly Li
2018-01-26 5:51 ` Michael Lyle
2018-01-26 6:23 ` Coly Li
2018-02-16 12:11 ` Nix
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