| Message ID | 20210805124645.543797-1-yukuai3@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit() | expand |
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.
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.
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); }
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(-)