Re: [PATCH] drm/nouveau/dispnv04: fix a possible null pointer dereference

From: Danilo Krummrich
Date: Thu Oct 12 2023 - 13:58:59 EST


On 10/7/23 05:23, Ma Ke wrote:
In nv17_tv_get_ld_modes(), the return value of drm_mode_duplicate()
is assigned to mode, which will lead to a NULL pointer dereference
on failure of drm_mode_duplicate(). Add a check to avoid npd.

Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>

Reviewed-by: Danilo Krummrich <dakr@xxxxxxxxxx>

---
drivers/gpu/drm/nouveau/dispnv04/tvnv17.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
index 670c9739e5e1..4a08e61f3336 100644
--- a/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
+++ b/drivers/gpu/drm/nouveau/dispnv04/tvnv17.c
@@ -209,6 +209,8 @@ static int nv17_tv_get_ld_modes(struct drm_encoder *encoder,
struct drm_display_mode *mode;
mode = drm_mode_duplicate(encoder->dev, tv_mode);
+ if (!mode)
+ continue;
mode->clock = tv_norm->tv_enc_mode.vrefresh *
mode->htotal / 1000 *