Patchwork block: Fix multiwrite error handling

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Submitter Kevin Wolf
Date April 1, 2010, 8:48 p.m.
Message ID <1270154924-10400-1-git-send-email-kwolf@redhat.com>
Download mbox | patch
Permalink /patch/49244/
State New
Headers show

Comments

Kevin Wolf - April 1, 2010, 8:48 p.m.
When two requests of the same multiwrite batch fail, the callback of all
requests in that batch were called twice. This could have any kind of nasty
effects, in my case it lead to use after free and eventually a segfault.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
Aurelien Jarno - April 9, 2010, 10:14 p.m.
On Thu, Apr 01, 2010 at 10:48:44PM +0200, Kevin Wolf wrote:
> When two requests of the same multiwrite batch fail, the callback of all
> requests in that batch were called twice. This could have any kind of nasty
> effects, in my case it lead to use after free and eventually a segfault.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Thanks, applied.

> ---
>  block.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/block.c b/block.c
> index 31610af..1c36e91 100644
> --- a/block.c
> +++ b/block.c
> @@ -1734,7 +1734,7 @@ static void multiwrite_cb(void *opaque, int ret)
>  {
>      MultiwriteCB *mcb = opaque;
>  
> -    if (ret < 0) {
> +    if (ret < 0 && !mcb->error) {
>          mcb->error = ret;
>          multiwrite_user_cb(mcb);
>      }
> -- 
> 1.6.6.1
> 
> 
> 
>

Patch

diff --git a/block.c b/block.c
index 31610af..1c36e91 100644
--- a/block.c
+++ b/block.c
@@ -1734,7 +1734,7 @@  static void multiwrite_cb(void *opaque, int ret)
 {
     MultiwriteCB *mcb = opaque;
 
-    if (ret < 0) {
+    if (ret < 0 && !mcb->error) {
         mcb->error = ret;
         multiwrite_user_cb(mcb);
     }