[PATCH 5.15 154/279] scsi: ufs: core: Fix task management completion timeout race

Greg Kroah-Hartman
2021-11-24T13:58:15Z

From: Adrian Hunter <adrian.hunter@intel.com>

[ Upstream commit 886fe2915cce6658b0fc19e64b82879325de61ea ]

__ufshcd_issue_tm_cmd() clears req->end_io_data after timing out, which
races with the completion function ufshcd_tmc_handler() which expects
req->end_io_data to have a value.

Note __ufshcd_issue_tm_cmd() and ufshcd_tmc_handler() are already
synchronized using hba->tmf_rqs and hba->outstanding_tasks under the
host_lock spinlock.

It is also not necessary (nor typical) to clear req->end_io_data because
the block layer does it before allocating out requests e.g. via
blk_get_request().

So fix by not clearing it.

Link: https://lore.kernel.org/r/20211108064815.569494-2-adrian.hunter@intel.com
Fixes: f5ef336fd2e4 ("scsi: ufs: core: Fix task management completion")
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/ufs/ufshcd.c | 5 -----
1 file changed, 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 325a15186e950..3d0da8b3fed8a 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6541,11 +6541,6 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
err = wait_for_completion_io_timeout(&wait,
msecs_to_jiffies(TM_CMD_TIMEOUT));
if (!err) {
- /*
- * Make sure that ufshcd_compl_tm() does not trigger a
- * use-after-free.
- */
- req->end_io_data = NULL;
ufshcd_add_tm_upiu_trace(hba, task_tag, UFS_TM_ERR);
dev_err(hba->dev, "%s: task management cmd 0x%.2x timed-out\n",
__func__, tm_function);
--
2.33.0