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[Qemu-devel] [PATCH for-2.1] block/cow: Avoid use of uninitialized cow_b
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH for-2.1] block/cow: Avoid use of uninitialized cow_bs in error path |
Date: |
Mon, 30 Jun 2014 19:03:37 +0100 |
Commit 25814e8987 introduced an error-exit code path which does
a "goto exit" before the cow_bs variable is initialized, meaning
we would call bdrv_unref() on an uninitialized variable and
likely segfault. Fix this by moving the NULL-initialization
to the top of the function and making the exit code path handle
the case where it is NULL.
Signed-off-by: Peter Maydell <address@hidden>
---
block/cow.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/block/cow.c b/block/cow.c
index 8f81ee6..6ee4833 100644
--- a/block/cow.c
+++ b/block/cow.c
@@ -332,7 +332,7 @@ static int cow_create(const char *filename, QemuOpts *opts,
Error **errp)
char *image_filename = NULL;
Error *local_err = NULL;
int ret;
- BlockDriverState *cow_bs;
+ BlockDriverState *cow_bs = NULL;
/* Read out options */
image_sectors = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0) / 512;
@@ -344,7 +344,6 @@ static int cow_create(const char *filename, QemuOpts *opts,
Error **errp)
goto exit;
}
- cow_bs = NULL;
ret = bdrv_open(&cow_bs, filename, NULL, NULL,
BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err);
if (ret < 0) {
@@ -383,7 +382,9 @@ static int cow_create(const char *filename, QemuOpts *opts,
Error **errp)
exit:
g_free(image_filename);
- bdrv_unref(cow_bs);
+ if (cow_bs) {
+ bdrv_unref(cow_bs);
+ }
return ret;
}
--
1.9.1
- [Qemu-devel] [PATCH for-2.1] block/cow: Avoid use of uninitialized cow_bs in error path,
Peter Maydell <=