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| author | Xiubo Li <xiubli@redhat.com> | 2019-09-19 09:14:27 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-06 15:08:44 +0300 |
| commit | 1df6bb8ce8ababaee2d66add746235a73e5df2db (patch) | |
| tree | 4af63a6a5b874e6adc92b8ae6a2b80a0abe364ee | |
| parent | 2ef37b2c9c6820db58c6c5c782e032ff3463f319 (diff) | |
| download | linux-1df6bb8ce8ababaee2d66add746235a73e5df2db.tar.xz | |
nbd: fix possible sysfs duplicate warning
[ Upstream commit 862488105b84ca744b3d8ff131e0fcfe10644be1 ]
1. nbd_put takes the mutex and drops nbd->ref to 0. It then does
idr_remove and drops the mutex.
2. nbd_genl_connect takes the mutex. idr_find/idr_for_each fails
to find an existing device, so it does nbd_dev_add.
3. just before the nbd_put could call nbd_dev_remove or not finished
totally, but if nbd_dev_add try to add_disk, we can hit:
debugfs: Directory 'nbd1' with parent 'block' already present!
This patch will make sure all the disk add/remove stuff are done
by holding the nbd_index_mutex lock.
Reported-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/block/nbd.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 0b727f7432f9..bd164192045b 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -230,8 +230,8 @@ static void nbd_put(struct nbd_device *nbd) if (refcount_dec_and_mutex_lock(&nbd->refs, &nbd_index_mutex)) { idr_remove(&nbd_index_idr, nbd->index); - mutex_unlock(&nbd_index_mutex); nbd_dev_remove(nbd); + mutex_unlock(&nbd_index_mutex); } } |