qcow2: Fix segfault on zero-length write

PATCH Applied Kevin Wolf 2 participants 2 messages Jan 14, 2013 – Jan 15, 2013 Block layer

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Kevin Wolf

author

2013-01-14 16:31 UTC #0 lore raw

PATCH 1/1 qcow2: Fix segfault on zero-length write

One of the recent refactoring patches (commit f50f88b9) didn't take care to initialise l2meta properly, so with zero-length writes, which don't even enter the write loop, qemu just segfaulted.

Signed-off-by Kevin Wolf <[email protected]>

---
 block/qcow2.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

block/qcow2.c +1 -1

index 76c86a7..9c64917 100644
@@ -759,7 +759,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
     QEMUIOVector hd_qiov;
     uint64_t bytes_done = 0;
     uint8_t *cluster_data = NULL;
-    QCowL2Meta *l2meta;
+    QCowL2Meta *l2meta = NULL;
 
     trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
                                  remaining_sectors);

Signature · 1 line

1.7.6.5

Stefan Hajnoczi

Applied

2013-01-15 08:17 UTC #1 lore raw

Quoted 8 lines · Kevin Wolf

One of the recent refactoring patches (commit f50f88b9) didn't take care to initialise l2meta properly, so with zero-length writes, which don't even enter the write loop, qemu just segfaulted.
Signed-off-by Kevin Wolf <[email protected]>
---
 block/qcow2.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan