[PATCH 5.15 140/207] drm/vc4: kms: Fix return code check

Greg Kroah-Hartman
2021-12-06T15:53:16Z

From: Maxime Ripard <maxime@cerno.tech>

commit f927767978d201d4ac023fcd797adbb963a6565d upstream.

The HVS global state functions return an error pointer, but in most
cases we check if it's NULL, possibly resulting in an invalid pointer
dereference.

Fixes: 9ec03d7f1ed3 ("drm/vc4: kms: Wait on previous FIFO users before a commit")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-by: Jian-Hong Pan <jhp@endlessos.org>
Link: https://lore.kernel.org/r/20211117094527.146275-3-maxime@cerno.tech
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/vc4/vc4_kms.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_kms.c
+++ b/drivers/gpu/drm/vc4/vc4_kms.c
@@ -354,7 +354,7 @@ static void vc4_atomic_commit_tail(struc
}

old_hvs_state = vc4_hvs_get_old_global_state(state);
- if (!old_hvs_state)
+ if (IS_ERR(old_hvs_state))
return;

for_each_old_crtc_in_state(state, crtc, old_crtc_state, i) {
@@ -410,8 +410,8 @@ static int vc4_atomic_commit_setup(struc
unsigned int i;

hvs_state = vc4_hvs_get_new_global_state(state);
- if (!hvs_state)
- return -EINVAL;
+ if (WARN_ON(IS_ERR(hvs_state)))
+ return PTR_ERR(hvs_state);

for_each_new_crtc_in_state(state, crtc, crtc_state, i) {
struct vc4_crtc_state *vc4_crtc_state =
@@ -762,8 +762,8 @@ static int vc4_pv_muxing_atomic_check(st
unsigned int i;

hvs_new_state = vc4_hvs_get_global_state(state);
- if (!hvs_new_state)
- return -EINVAL;
+ if (IS_ERR(hvs_new_state))
+ return PTR_ERR(hvs_new_state);

for (i = 0; i < ARRAY_SIZE(hvs_new_state->fifo_state); i++)
if (!hvs_new_state->fifo_state[i].in_use)