public inbox for intel-gfx@lists.freedesktop.org
 help / color / mirror / Atom feed
* [Intel-gfx] [PATCH] drm/i915/dp: prevent potential div-by-zero
@ 2023-04-18 14:04 Nikita Zhandarovich
  2023-04-21 19:24 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Nikita Zhandarovich @ 2023-04-18 14:04 UTC (permalink / raw)
  To: Jani Nikula
  Cc: Nikita Zhandarovich, intel-gfx, Jason A. Donenfeld, dri-devel,
	linux-kernel, Manasi Navare, Daniel Vetter, Rodrigo Vivi,
	David Airlie, lvc-project

drm_dp_dsc_sink_max_slice_count() may return 0 if something goes
wrong on the part of the DSC sink and its DPCD register. This null
value may be later used as a divisor in intel_dsc_compute_params(),
which will lead to an error.
In the unlikely event that this issue occurs, fix it by testing the
return value of drm_dp_dsc_sink_max_slice_count() against zero.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: a4a157777c80 ("drm/i915/dp: Compute DSC pipe config in atomic check")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 62cbab7402e9..c1825f8f885c 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1533,6 +1533,11 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
 		pipe_config->dsc.slice_count =
 			drm_dp_dsc_sink_max_slice_count(intel_dp->dsc_dpcd,
 							true);
+		if (!pipe_config->dsc.slice_count) {
+			drm_dbg_kms(&dev_priv->drm, "Unsupported Slice Count %d\n",
+				    pipe_config->dsc.slice_count);
+			return -EINVAL;
+		}
 	} else {
 		u16 dsc_max_output_bpp = 0;
 		u8 dsc_dp_slice_count;
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-05-05 14:29 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-04-18 14:04 [Intel-gfx] [PATCH] drm/i915/dp: prevent potential div-by-zero Nikita Zhandarovich
2023-04-21 19:24 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2023-04-22  5:23 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2023-05-05 14:29 ` [Intel-gfx] [PATCH] " Rodrigo Vivi

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox