diff options
| author | Fiona Ebner <f.ebner@proxmox.com> | 2023-10-19 15:19:36 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2023-10-31 13:51:36 +0100 |
| commit | 302823854b078f0525cf1babcc4fc9ff7b7d5f71 (patch) | |
| tree | 12ffe2f508a27a27404bd8ae1aa1d0c9c23d215a /blockdev.c | |
| parent | e462c6d27d0175a67cd373b3027ea5276d25dd4e (diff) | |
blockdev: mirror: avoid potential deadlock when using iothread
The bdrv_getlength() function is a generated co-wrapper and uses
AIO_WAIT_WHILE() to wait for the spawned coroutine. AIO_WAIT_WHILE()
expects the lock to be acquired exactly once.
Fix a case where it may be acquired twice. This can happen when the
source node is explicitly specified as the @replaces parameter or if the
source node is a filter node.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20231019131936.414246-4-f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'blockdev.c')
| -rw-r--r-- | blockdev.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/blockdev.c b/blockdev.c index a01c62596b..877e3a26d4 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2968,6 +2968,7 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, if (replaces) { BlockDriverState *to_replace_bs; + AioContext *aio_context; AioContext *replace_aio_context; int64_t bs_size, replace_size; @@ -2982,10 +2983,19 @@ static void blockdev_mirror_common(const char *job_id, BlockDriverState *bs, return; } + aio_context = bdrv_get_aio_context(bs); replace_aio_context = bdrv_get_aio_context(to_replace_bs); - aio_context_acquire(replace_aio_context); + /* + * bdrv_getlength() is a co-wrapper and uses AIO_WAIT_WHILE. Be sure not + * to acquire the same AioContext twice. + */ + if (replace_aio_context != aio_context) { + aio_context_acquire(replace_aio_context); + } replace_size = bdrv_getlength(to_replace_bs); - aio_context_release(replace_aio_context); + if (replace_aio_context != aio_context) { + aio_context_release(replace_aio_context); + } if (replace_size < 0) { error_setg_errno(errp, -replace_size, |