[PATCH 2/2] drm/nouveau: Fix NULL pointer dereference in GET_ZCULL_INFO ioctl
Jim Cromie <[email protected]>
| Newsgroups | org.freedesktop.lists.nouveau,org.freedesktop.lists.dri-devel,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
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 <[email protected]> --- 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