[PATCH v3] drm/xe/xe_devcoredump: Check NULL before dereferencing

[Himal Prasad Ghimiray]

Dereference 'coredump' to access 'xe_devcoredump_snapshot' only if
'coredump' is not NULL,

v2
- Fix commit messages.

v3
- Define variables before code.(Ashutosh/Jose)

Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/xe/xe_devcoredump.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_devcoredump.c b/drivers/gpu/drm/xe/xe_devcoredump.c
index 7d3aa6bd3524..5b7be3b5b906 100644
--- a/drivers/gpu/drm/xe/xe_devcoredump.c
+++ b/drivers/gpu/drm/xe/xe_devcoredump.c
@@ -77,17 +77,22 @@ static ssize_t xe_devcoredump_read(char *buffer, loff_t offset,
 				   size_t count, void *data, size_t datalen)
 {
 	struct xe_devcoredump *coredump = data;
-	struct xe_device *xe = coredump_to_xe(coredump);
-	struct xe_devcoredump_snapshot *ss = &coredump->snapshot;
+	struct xe_device *xe;
+	struct xe_devcoredump_snapshot *ss;
 	struct drm_printer p;
 	struct drm_print_iterator iter;
 	struct timespec64 ts;
 	int i;
 
-	/* Our device is gone already... */
-	if (!data || !coredump_to_xe(coredump))
+	if (!coredump)
+		return -ENODATA;
+
+	xe = coredump_to_xe(coredump);
+	if (!xe)
 		return -ENODEV;
 
+	ss = &coredump->snapshot;
+
 	/* Ensure delayed work is captured before continuing */
 	flush_work(&ss->work);
 
-- 
2.25.1