* [PATCH] block: null_blk: fix use after free
@ 2014-05-01 7:12 Ming Lei
2014-05-01 15:17 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Ming Lei @ 2014-05-01 7:12 UTC (permalink / raw)
To: Jens Axboe, linux-kernel; +Cc: Christoph Hellwig, Ming Lei
entry(cmd->ll_list) may belong to new request once end_cmd()
returns, so fix the bug with the patch.
Without the change, it is easy to observe oops when
doing null_blk(timer) test.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
---
drivers/block/null_blk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 8e7e3a0..e932398 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -203,8 +203,8 @@ static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
entry = llist_reverse_order(entry);
do {
cmd = container_of(entry, struct nullb_cmd, ll_list);
- end_cmd(cmd);
entry = entry->next;
+ end_cmd(cmd);
} while (entry);
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] block: null_blk: fix use after free
2014-05-01 7:12 [PATCH] block: null_blk: fix use after free Ming Lei
@ 2014-05-01 15:17 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2014-05-01 15:17 UTC (permalink / raw)
To: Ming Lei, linux-kernel; +Cc: Christoph Hellwig
On 05/01/2014 01:12 AM, Ming Lei wrote:
> entry(cmd->ll_list) may belong to new request once end_cmd()
> returns, so fix the bug with the patch.
>
> Without the change, it is easy to observe oops when
> doing null_blk(timer) test.
>
> Signed-off-by: Ming Lei <tom.leiming@gmail.com>
> ---
> drivers/block/null_blk.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
> index 8e7e3a0..e932398 100644
> --- a/drivers/block/null_blk.c
> +++ b/drivers/block/null_blk.c
> @@ -203,8 +203,8 @@ static enum hrtimer_restart null_cmd_timer_expired(struct hrtimer *timer)
> entry = llist_reverse_order(entry);
> do {
> cmd = container_of(entry, struct nullb_cmd, ll_list);
> - end_cmd(cmd);
> entry = entry->next;
> + end_cmd(cmd);
> } while (entry);
> }
Good catch, applied.
--
Jens Axboe
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2014-05-01 15:17 ` Jens Axboe
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