From: Mike Christie <mchristi@redhat.com>
To: Dan Carpenter <dan.carpenter@oracle.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Bodo Stroesser <bstroesser@ts.fujitsu.com>
Cc: linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd()
Date: Sat, 23 May 2020 14:04:14 -0500 [thread overview]
Message-ID: <0d4b569b-f21f-43f3-b25c-0b4c06cbe718@redhat.com> (raw)
In-Reply-To: <20200523101129.GB98132@mwanda>
On 5/23/20 5:11 AM, Dan Carpenter wrote:
> The pr_debug() dereferences "cmd" after we already freed it by calling
> tcmu_free_cmd(cmd). The debug printk needs to be done earlier.
>
> Fixes: 61fb24822166 ("scsi: target: tcmu: Userspace must not complete queued commands")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> drivers/target/target_core_user.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
> index 904d8a8373f2..28fb9441de7a 100644
> --- a/drivers/target/target_core_user.c
> +++ b/drivers/target/target_core_user.c
> @@ -1292,13 +1292,13 @@ static void tcmu_check_expired_queue_cmd(struct tcmu_cmd *cmd)
> if (!time_after(jiffies, cmd->deadline))
> return;
>
> + pr_debug("Timing out queued cmd %p on dev %s.\n",
> + cmd, cmd->tcmu_dev->name);
> +
> list_del_init(&cmd->queue_entry);
> se_cmd = cmd->se_cmd;
> tcmu_free_cmd(cmd);
>
> - pr_debug("Timing out queued cmd %p on dev %s.\n",
> - cmd, cmd->tcmu_dev->name);
> -
> target_complete_cmd(se_cmd, SAM_STAT_TASK_SET_FULL);
> }
>
Thanks.
Reviewed-by: Mike Christie <mchristi@redhat.com>
next prev parent reply other threads:[~2020-05-23 19:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 10:11 [PATCH] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd() Dan Carpenter
2020-05-23 13:03 ` David Disseldorp
2020-05-23 19:04 ` Mike Christie [this message]
2020-05-25 9:11 ` Bodo Stroesser
2020-05-26 12:26 ` Dan Carpenter
2020-05-27 2:12 ` Martin K. Petersen
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