In the Linux kernel, the following vulnerability has been resolved: drm/i915/gvt: fix gvt debugfs destroy When gvt debug fs is destroyed, need to have a sane check if drm minor's debugfs root is still available or not, otherwise in case like device remove through unbinding, drm minor's debugfs directory has already been removed, then intelgvtdebugfsclean() would act upon dangling pointer like below oops. i915 0000:00:02.0: Direct firmware load for i915/gvt/vid0x8086did0x1926rid0x0a.goldenhwstate failed with error -2 i915 0000:00:02.0: MDEV: Registered Console: switching to colour dummy device 80x25 i915 0000:00:02.0: MDEV: Unregistering BUG: kernel NULL pointer dereference, address: 00000000000000a0 PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP PTI CPU: 2 PID: 2486 Comm: gfx-unbind.sh Tainted: G I 6.1.0-rc8+ #15 Hardware name: Dell Inc. XPS 13 9350/0JXC1H, BIOS 1.13.0 02/10/2020 RIP: 0010:downwrite+0x1f/0x90 Code: 1d ff ff 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 53 48 89 fb e8 62 c0 ff ff bf 01 00 00 00 e8 28 5e 31 ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 13 75 33 65 48 8b 04 25 c0 bd 01 00 48 89 43 08 bf 01 RSP: 0018:ffff9eb3036ffcc8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00000000000000a0 RCX: ffffff8100000000 RDX: 0000000000000001 RSI: 0000000000000064 RDI: ffffffffa48787a8 RBP: ffff9eb3036ffd30 R08: ffffeb1fc45a0608 R09: ffffeb1fc45a05c0 R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000 R13: ffff91acc33fa328 R14: ffff91acc033f080 R15: ffff91acced533e0 FS: 00007f6947bba740(0000) GS:ffff91ae36d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000a0 CR3: 00000001133a2002 CR4: 00000000003706e0 Call Trace: <TASK> simplerecursiveremoval+0x9f/0x2a0 ? startcreating.part.0+0x120/0x120 ? rawspinlock+0x13/0x40 debugfsremove+0x40/0x60 intelgvtdebugfsclean+0x15/0x30 [kvmgt] intelgvtcleandevice+0x49/0xe0 [kvmgt] intelgvtdriverremove+0x2f/0xb0 i915driverremove+0xa4/0xf0 i915pciremove+0x1a/0x30 pcideviceremove+0x33/0xa0 devicereleasedriverinternal+0x1b2/0x230 unbindstore+0xe0/0x110 kernfsfopwriteiter+0x11b/0x1f0 vfswrite+0x203/0x3d0 ksyswrite+0x63/0xe0 dosyscall64+0x37/0x90 entrySYSCALL64afterhwframe+0x63/0xcd RIP: 0033:0x7f6947cb5190 Code: 40 00 48 8b 15 71 9c 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 80 3d 51 24 0e 00 00 74 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 48 89 RSP: 002b:00007ffcbac45a28 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f6947cb5190 RDX: 000000000000000d RSI: 0000555e35c866a0 RDI: 0000000000000001 RBP: 0000555e35c866a0 R08: 0000000000000002 R09: 0000555e358cb97c R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000001 R13: 000000000000000d R14: 0000000000000000 R15: 0000555e358cb8e0 </TASK> Modules linked in: kvmgt CR2: 00000000000000a0 ---[ end trace 0000000000000000 ]---