* [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 12:46 ` Yu Kuai
0 siblings, 0 replies; 6+ messages in thread
From: Yu Kuai @ 2021-08-05 12:46 UTC (permalink / raw)
To: tj, axboe, bo.liu; +Cc: cgroups, linux-block, linux-kernel, yukuai3, yi.zhang
If queue is dying while iolatency_set_limit() is in progress,
blk_get_queue() won't increment the refcount of the queue. However,
blk_put_queue() will still decrement the refcount later, which will
cause the refcout to be unbalanced.
Thus error out in such case to fix the problem.
Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
block/blk-iolatency.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 81be0096411d..d8b0d8bd132b 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -833,7 +833,11 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
enable = iolatency_set_min_lat_nsec(blkg, lat_val);
if (enable) {
- WARN_ON_ONCE(!blk_get_queue(blkg->q));
+ if (!blk_get_queue(blkg->q)) {
+ ret = -ENODEV;
+ goto out;
+ }
+
blkg_get(blkg);
}
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 12:46 ` Yu Kuai
0 siblings, 0 replies; 6+ messages in thread
From: Yu Kuai @ 2021-08-05 12:46 UTC (permalink / raw)
To: tj-DgEjT+Ai2ygdnm+yROfE0A, axboe-tSWWG44O7X1aa/9Udqfwiw,
bo.liu-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-block-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
yukuai3-hv44wF8Li93QT0dZR+AlfA, yi.zhang-hv44wF8Li93QT0dZR+AlfA
If queue is dying while iolatency_set_limit() is in progress,
blk_get_queue() won't increment the refcount of the queue. However,
blk_put_queue() will still decrement the refcount later, which will
cause the refcout to be unbalanced.
Thus error out in such case to fix the problem.
Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter")
Signed-off-by: Yu Kuai <yukuai3-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
block/blk-iolatency.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 81be0096411d..d8b0d8bd132b 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -833,7 +833,11 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
enable = iolatency_set_min_lat_nsec(blkg, lat_val);
if (enable) {
- WARN_ON_ONCE(!blk_get_queue(blkg->q));
+ if (!blk_get_queue(blkg->q)) {
+ ret = -ENODEV;
+ goto out;
+ }
+
blkg_get(blkg);
}
--
2.31.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 17:17 ` Tejun Heo
0 siblings, 0 replies; 6+ messages in thread
From: Tejun Heo @ 2021-08-05 17:17 UTC (permalink / raw)
To: Yu Kuai; +Cc: axboe, bo.liu, cgroups, linux-block, linux-kernel, yi.zhang
On Thu, Aug 05, 2021 at 08:46:45PM +0800, Yu Kuai wrote:
> If queue is dying while iolatency_set_limit() is in progress,
> blk_get_queue() won't increment the refcount of the queue. However,
> blk_put_queue() will still decrement the refcount later, which will
> cause the refcout to be unbalanced.
>
> Thus error out in such case to fix the problem.
>
> Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter")
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 17:17 ` Tejun Heo
0 siblings, 0 replies; 6+ messages in thread
From: Tejun Heo @ 2021-08-05 17:17 UTC (permalink / raw)
To: Yu Kuai
Cc: axboe-tSWWG44O7X1aa/9Udqfwiw,
bo.liu-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf,
cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-block-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
yi.zhang-hv44wF8Li93QT0dZR+AlfA
On Thu, Aug 05, 2021 at 08:46:45PM +0800, Yu Kuai wrote:
> If queue is dying while iolatency_set_limit() is in progress,
> blk_get_queue() won't increment the refcount of the queue. However,
> blk_put_queue() will still decrement the refcount later, which will
> cause the refcout to be unbalanced.
>
> Thus error out in such case to fix the problem.
>
> Fixes: 8c772a9bfc7c ("blk-iolatency: fix IO hang due to negative inflight counter")
> Signed-off-by: Yu Kuai <yukuai3-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Acked-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 17:18 ` Jens Axboe
0 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2021-08-05 17:18 UTC (permalink / raw)
To: Yu Kuai, tj, bo.liu; +Cc: cgroups, linux-block, linux-kernel, yi.zhang
On 8/5/21 6:46 AM, Yu Kuai wrote:
> If queue is dying while iolatency_set_limit() is in progress,
> blk_get_queue() won't increment the refcount of the queue. However,
> blk_put_queue() will still decrement the refcount later, which will
> cause the refcout to be unbalanced.
>
> Thus error out in such case to fix the problem.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
@ 2021-08-05 17:18 ` Jens Axboe
0 siblings, 0 replies; 6+ messages in thread
From: Jens Axboe @ 2021-08-05 17:18 UTC (permalink / raw)
To: Yu Kuai, tj-DgEjT+Ai2ygdnm+yROfE0A,
bo.liu-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA,
linux-block-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
yi.zhang-hv44wF8Li93QT0dZR+AlfA
On 8/5/21 6:46 AM, Yu Kuai wrote:
> If queue is dying while iolatency_set_limit() is in progress,
> blk_get_queue() won't increment the refcount of the queue. However,
> blk_put_queue() will still decrement the refcount later, which will
> cause the refcout to be unbalanced.
>
> Thus error out in such case to fix the problem.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-08-05 17:18 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-05 12:46 [PATCH] blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() Yu Kuai
2021-08-05 12:46 ` Yu Kuai
2021-08-05 17:17 ` Tejun Heo
2021-08-05 17:17 ` Tejun Heo
2021-08-05 17:18 ` Jens Axboe
2021-08-05 17:18 ` Jens Axboe
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