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| author | Max Reitz <mreitz@redhat.com> | 2014-03-10 23:44:07 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-03-13 14:23:27 +0100 |
| commit | dba2855572c746836ad90ce9154403b5929d996b (patch) | |
| tree | e6f4d87aca3c7b9d74ebc6cacbba7040f4f6d8cb | |
| parent | 3456a8d1852e970688b73d03fdc44dde851759e1 (diff) | |
| download | qemu-dba2855572c746836ad90ce9154403b5929d996b.zip qemu-dba2855572c746836ad90ce9154403b5929d996b.tar.gz qemu-dba2855572c746836ad90ce9154403b5929d996b.tar.bz2 | |
qcow2: Check bs->drv in copy_sectors()
Before dereferencing bs->drv for a call to its member bdrv_co_readv(),
copy_sectors() should check whether that pointer is indeed valid, since
it may have been set to NULL by e.g. a concurrent write triggering the
corruption prevention mechanism.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | block/qcow2-cluster.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 36c1bed..9499df9 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -380,6 +380,10 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs, BLKDBG_EVENT(bs->file, BLKDBG_COW_READ); + if (!bs->drv) { + return -ENOMEDIUM; + } + /* Call .bdrv_co_readv() directly instead of using the public block-layer * interface. This avoids double I/O throttling and request tracking, * which can lead to deadlock when block layer copy-on-read is enabled. |