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From: Defang Bo <bodefang@126.com>
To: airlied@linux.ie, daniel@ffwll.ch
Cc: stylon.wang@amd.com, luben.tuikov@amd.com, amonakov@ispras.ru,
	Rodrigo.Siqueira@amd.com, linux-kernel@vger.kernel.org,
	amd-gfx@lists.freedesktop.org, aurabindo.pillai@amd.com,
	hersenxs.wu@amd.com, Defang Bo <bodefang@126.com>,
	Bhawanpreet.Lakha@amd.com, nicholas.kazlauskas@amd.com
Subject: [PATCH] drm/amd/display: avoid null pointer dereference in dm_set_vblank
Date: Mon, 28 Dec 2020 11:57:06 +0800	[thread overview]
Message-ID: <1609127826-264749-1-git-send-email-bodefang@126.com> (raw)

[Why]
Similar to commit<dddc0557e3a0>("drm/amd/display: Guard against null crtc in CRC IRQ"), a null pointer deference can occur if crtc is null in
dm_set_vblank.

[How]
Check that CRTC is non-null before accessing its fields.

Signed-off-by: Defang Bo <bodefang@126.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index e2b23486..f820962 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4875,11 +4875,19 @@ static inline int dm_set_vupdate_irq(struct drm_crtc *crtc, bool enable)
 static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable)
 {
 	enum dc_irq_source irq_source;
-	struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc);
-	struct amdgpu_device *adev = drm_to_adev(crtc->dev);
-	struct dm_crtc_state *acrtc_state = to_dm_crtc_state(crtc->state);
+	struct amdgpu_crtc *acrtc;
+	struct amdgpu_device *adev;
+	struct dm_crtc_state *acrtc_state;
 	int rc = 0;
 
+	if (crtc == NULL)
+		return -EINVAL;
+
+	acrtc = to_amdgpu_crtc(crtc);
+	adev = drm_to_adev(crtc->dev);
+	acrtc_state = to_dm_crtc_state(crtc->state);
+
+
 	if (enable) {
 		/* vblank irq on -> Only need vupdate irq in vrr mode */
 		if (amdgpu_dm_vrr_active(acrtc_state))
-- 
2.7.4

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             reply	other threads:[~2020-12-28 10:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-28  3:57 Defang Bo [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-12-25  6:24 [PATCH] drm/amd/display: avoid null pointer dereference in dm_set_vblank Defang Bo

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