dmaengine: idxd: Fix potential null dereference on pointer status

There are calls to idxd_cmd_exec that pass a null status pointer however
a recent commit has added an assignment to *status that can end up
with a null pointer dereference.  The function expects a null status
pointer sometimes as there is a later assignment to *status where
status is first null checked.  Fix the issue by null checking status
before making the assignment.

Addresses-Coverity: ("Explicit null dereferenced")
Fixes: 89e3becd8f82 ("dmaengine: idxd: check device state before issue command")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20210415110654.1941580-1-colin.king@canonical.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 84a6ea6..90b875b 100644 (file)
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -445,7 +445,8 @@ static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,
 
        if (idxd_device_is_halted(idxd)) {
                dev_warn(&idxd->pdev->dev, "Device is HALTED!\n");
-               *status = IDXD_CMDSTS_HW_ERR;
+               if (status)
+                       *status = IDXD_CMDSTS_HW_ERR;
                return;
        }