[PATCH] staging: media: ipu7: add NULL checks before ipu7_mmu_cleanup() in remove

[Alfie Varghese <alfievarghese22@gmail.com>]

ipu7_pci_remove() calls ipu7_mmu_cleanup() on isp->isys->mmu and
isp->psys->mmu without checking whether isys or psys are valid
pointers. If ipu7_pci_probe() partially failed and left isys or psys
as NULL or an error pointer, the remove path will dereference a bad
pointer and crash the kernel.

The probe error cleanup path already guards these calls correctly with
IS_ERR_OR_NULL() checks. Apply the same guards in ipu7_pci_remove().

Signed-off-by: Alfie Varghese <alfievarghese22@gmail.com>
---
 drivers/staging/media/ipu7/ipu7.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/ipu7/ipu7.c b/drivers/staging/media/ipu7/ipu7.c
index 310e3f24e571..41436f22c684 100644
--- a/drivers/staging/media/ipu7/ipu7.c
+++ b/drivers/staging/media/ipu7/ipu7.c
@@ -2637,8 +2637,10 @@ static void ipu7_pci_remove(struct pci_dev *pdev)
 	if (!IS_ERR_OR_NULL(isp->fw_code_region))
 		vfree(isp->fw_code_region);
 
-	ipu7_mmu_cleanup(isp->isys->mmu);
-	ipu7_mmu_cleanup(isp->psys->mmu);
+	if (!IS_ERR_OR_NULL(isp->isys) && !IS_ERR_OR_NULL(isp->isys->mmu))
+		ipu7_mmu_cleanup(isp->isys->mmu);
+	if (!IS_ERR_OR_NULL(isp->psys) && !IS_ERR_OR_NULL(isp->psys->mmu))
+		ipu7_mmu_cleanup(isp->psys->mmu);
 
 	ipu7_bus_del_devices(pdev);