------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline], CPU#2: syz.5.1062/10130 WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x944/0x1bd0 kernel/locking/mutex.c:821, CPU#2: syz.5.1062/10130 Modules linked in: CPU: 2 UID: 0 PID: 10130 Comm: syz.5.1062 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline] RIP: 0010:__mutex_lock+0x94b/0x1bd0 kernel/locking/mutex.c:821 Code: 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 c0 10 00 00 44 8b 05 e8 25 74 05 45 85 c0 75 13 48 8d 3d 9c 30 77 05 48 c7 c6 e0 f3 ef 8b <67> 48 0f b9 3a 90 e9 1b f8 ff ff 4d 8d a7 f0 0a 00 00 4c 89 e7 e8 RSP: 0018:ffffc9000d6cf7e0 EFLAGS: 00010246 RAX: 0000000000000003 RBX: ffff8880285351c0 RCX: 1ffffffff228a560 RDX: 0000000000000000 RSI: ffffffff8beff3e0 RDI: ffffffff914835c0 RBP: ffffc9000d6cf950 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880283bf360 FS: 0000000000000000(0000) GS:ffff8880d5d64000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f74fd95da08 CR3: 000000000eb96000 CR4: 0000000000352ef0 Call Trace: virtio_gpu_remove_from_restore_list drivers/gpu/drm/virtio/virtgpu_object.c:70 [inline] virtio_gpu_free_object+0xec/0x280 drivers/gpu/drm/virtio/virtgpu_object.c:106 drm_gem_object_free+0x60/0xa0 drivers/gpu/drm/drm_gem.c:1164 kref_put include/linux/kref.h:65 [inline] __drm_gem_object_put include/drm/drm_gem.h:562 [inline] drm_gem_object_put include/drm/drm_gem.h:575 [inline] drm_gem_object_put include/drm/drm_gem.h:572 [inline] drm_gem_dmabuf_release+0xd1/0xf0 drivers/gpu/drm/drm_prime.c:272 dma_buf_release+0x159/0x2d0 drivers/dma-buf/dma-buf.c:183 dentry_kill+0x2ce/0xc20 fs/dcache.c:831 finish_dput fs/dcache.c:1001 [inline] dput.part.0+0xd7/0x240 fs/dcache.c:1042 dput+0x1f/0x30 fs/dcache.c:1037 __fput+0x519/0xb50 fs/file_table.c:520 task_work_run+0x150/0x240 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x951/0x2ae0 kernel/exit.c:1008 do_group_exit+0xd5/0x2a0 kernel/exit.c:1151 get_signal+0x1ec7/0x21e0 kernel/signal.c:3039 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcfd915e98e Code: Unable to access opcode bytes at 0x7fcfd915e964. RSP: 002b:00007fcfda002f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: fffffffffffffdfc RBX: 00007fcfda0036c0 RCX: 00007fcfd915e98e RDX: 00007fcfda002fb0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fcfd9235024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcfd9426038 R14: 00007fcfd9425fa0 R15: 00007fff8a69edf8 ---------------- Code disassembly (best guess): 0: 0f b6 14 11 movzbl (%rcx,%rdx,1),%edx 4: 38 d0 cmp %dl,%al 6: 7c 08 jl 0x10 8: 84 d2 test %dl,%dl a: 0f 85 c0 10 00 00 jne 0x10d0 10: 44 8b 05 e8 25 74 05 mov 0x57425e8(%rip),%r8d # 0x57425ff 17: 45 85 c0 test %r8d,%r8d 1a: 75 13 jne 0x2f 1c: 48 8d 3d 9c 30 77 05 lea 0x577309c(%rip),%rdi # 0x57730bf 23: 48 c7 c6 e0 f3 ef 8b mov $0xffffffff8beff3e0,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 90 nop 30: e9 1b f8 ff ff jmp 0xfffff850 35: 4d 8d a7 f0 0a 00 00 lea 0xaf0(%r15),%r12 3c: 4c 89 e7 mov %r12,%rdi 3f: e8 .byte 0xe8