From 9d7464b18892332e35ff37f0b024429a1a9835e6 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Sat, 23 May 2020 13:11:29 +0300 Subject: [PATCH] scsi: target: tcmu: Fix a use after free in tcmu_check_expired_queue_cmd() The pr_debug() dereferences "cmd" after we already freed it by calling tcmu_free_cmd(cmd). The debug printk needs to be done earlier. Link: https://lore.kernel.org/r/20200523101129.GB98132@mwanda Fixes: 61fb24822166 ("scsi: target: tcmu: Userspace must not complete queued commands") Reviewed-by: Mike Christie Reviewed-by: David Disseldorp Signed-off-by: Dan Carpenter Signed-off-by: Martin K. Petersen --- 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 1d030d57c28c..0e281d30d81e 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); } -- 2.34.1