[PATCH 4.19 68/78] mmc: core: Fix NULL ptr crash from mmc_should_fail_request

From: Greg Kroah-Hartman
Date: Mon Mar 04 2019 - 03:31:06 EST


4.19-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>

commit e5723f95d6b493dd437f1199cacb41459713b32f upstream.

In case of CQHCI, mrq->cmd may be NULL for data requests (non DCMD).
In such case mmc_should_fail_request is directly dereferencing
mrq->cmd while cmd is NULL.
Fix this by checking for mrq->cmd pointer.

Fixes: 72a5af554df8 ("mmc: core: Add support for handling CQE requests")
Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/mmc/core/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -95,7 +95,7 @@ static void mmc_should_fail_request(stru
if (!data)
return;

- if (cmd->error || data->error ||
+ if ((cmd && cmd->error) || data->error ||
!should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
return;