commit 8d2497c3552e19a60e7a75d20976471ecb2a8e2b
author Kevin Wolf <kwolf@redhat.com> Mon Jan 14 17:31:31 2013 +0100
committer Stefan Hajnoczi <stefanha@redhat.com> Tue Jan 15 09:08:55 2013 +0100
tree d0059fd766a2d4a024d6d42a4f1a26dea4b3c8a5
parent cf7c3f0cb5a7129f57fa9e69d410d6a05031988c

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 <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

block/qcow2.c

diff --git a/block/qcow2.c b/block/qcow2.c
index d603f98..f6abff6 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -759,7 +759,7 @@
     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);