From: Jim Cromie <jim.cromie@gmail.com>
To: Lyude Paul <lyude@redhat.com>, Danilo Krummrich <dakr@kernel.org>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
David Airlie <airlied@gmail.com>,
Simona Vetter <simona@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
linux-kernel@vger.kernel.org, Jim Cromie <jim.cromie@gmail.com>
Subject: [PATCH 2/2] drm/nouveau: Fix NULL pointer dereference in GET_ZCULL_INFO ioctl
Date: Sat, 15 Aug 2026 11:30:53 -0600 [thread overview]
Message-ID: <20260815-null-fixes-v1-2-0df9dda951fb@gmail.com> (raw)
In-Reply-To: <20260815-null-fixes-v1-0-0df9dda951fb@gmail.com>
When graphics engine firmware fails to load or initialization aborts
early, nvxx_gr(drm) returns NULL. Calling DRM_IOCTL_NOUVEAU_GET_ZCULL_INFO
causes nouveau_abi16_ioctl_get_zcull_info() to dereference gr at offset
0xf0 without checking for NULL, triggering a kernel page fault.
Validate that gr is non-NULL before inspecting gr->has_zcull_info.
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
---
Aug 14 09:21:52 frodo kernel: BUG: kernel NULL pointer dereference, address: 00000000000000f0
Aug 14 09:21:52 frodo kernel: #PF: error_code(0x0000) - not-present page
Aug 14 09:21:52 frodo kernel: Oops: Oops: 0000 [#1] SMP NOPTI
Aug 14 09:21:52 frodo kernel: RIP: 0010:nouveau_abi16_ioctl_get_zcull_info+0x17/0xa0 [nouveau]
Aug 14 09:21:52 frodo kernel: Code: 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 48 8b 47 40 48 8b 00 48 8b 80 70 02 00 00 <80> b8 f0 00 00 00 00 74 72 8b 90 c0 00 00 00 89 16 8b 90 c4 00 00
Aug 14 09:21:52 frodo kernel: Call Trace:
Aug 14 09:21:52 frodo kernel: <TASK>
Aug 14 09:21:52 frodo kernel: drm_ioctl_kernel+0xae/0x100
Aug 14 09:21:52 frodo kernel: drm_ioctl+0x2e0/0x560
Aug 14 09:21:52 frodo kernel: ? __pfx_nouveau_abi16_ioctl_get_zcull_info+0x10/0x10 [nouveau]
Aug 14 09:21:52 frodo kernel: nouveau_drm_ioctl+0x58/0xc0 [nouveau]
Aug 14 09:21:52 frodo kernel: __x64_sys_ioctl+0xb9/0x100
Aug 14 09:21:52 frodo kernel: do_syscall_64+0xe2/0x560
Aug 14 09:21:52 frodo kernel: entry_SYSCALL_64_after_hwframe+0x76/0x7e
Aug 14 09:21:52 frodo kernel: </TASK>
---
drivers/gpu/drm/nouveau/nouveau_abi16.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_abi16.c b/drivers/gpu/drm/nouveau/nouveau_abi16.c
index c9270c5b0fac..f1026a716ff7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_abi16.c
+++ b/drivers/gpu/drm/nouveau/nouveau_abi16.c
@@ -357,7 +357,7 @@ nouveau_abi16_ioctl_get_zcull_info(ABI16_IOCTL_ARGS)
struct nvkm_gr *gr = nvxx_gr(drm);
struct drm_nouveau_get_zcull_info *out = data;
- if (gr->has_zcull_info) {
+ if (gr && gr->has_zcull_info) {
const struct nvkm_gr_zcull_info *i = &gr->zcull_info;
out->width_align_pixels = i->width_align_pixels;
--
2.55.0
prev parent reply other threads:[~2026-08-15 17:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-15 17:30 [PATCH 0/2] drm/nouveau: Fix NULL pointer dereferences in GETPARAM and GET_ZCULL_INFO ioctls Jim Cromie
2026-08-15 17:30 ` [PATCH 1/2] drm/nouveau: Fix NULL pointer dereferences in GETPARAM ioctl Jim Cromie
2026-08-15 17:30 ` Jim Cromie [this message]
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