------------[ cut here ]------------
WARNING: CPU: 1 PID: 24928 at drivers/gpu/drm/vkms/vkms_gem.c:37 vkms_gem_free_object+0x85/0xa0 drivers/gpu/drm/vkms/vkms_gem.c:37
Modules linked in:
CPU: 1 PID: 24928 Comm: syz-executor.3 Not tainted 5.9.0-rc2-next-20200828-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:vkms_gem_free_object+0x85/0xa0 drivers/gpu/drm/vkms/vkms_gem.c:37
Code: 00 75 2b e8 8d 54 0b fd 48 8d bd 30 02 00 00 e8 d1 13 f0 fc 48 89 ef e8 89 3a a5 ff 48 89 ef 5d e9 80 5b 4b fd e8 6b 54 0b fd <0f> 0b eb a8 e8 62 54 0b fd 0f 0b eb cc e8 b9 cf 4b fd eb bb e8 b2
RSP: 0018:ffffc90016007c08 EFLAGS: 00010216
RAX: 0000000000000bad RBX: ffffffff846927a0 RCX: ffffc9000f341000
RDX: 0000000000040000 RSI: ffffffff84692825 RDI: ffff88809548e2c0
RBP: ffff88809548e000 R08: 0000000000000001 R09: ffff88809548e003
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8882182b0c30
R13: ffff88809548e008 R14: ffff88809548e128 R15: ffff88809f562000
FS:  00007f3615f91700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000096e39000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 drm_gem_object_free drivers/gpu/drm/drm_gem.c:990 [inline]
 kref_put include/linux/kref.h:65 [inline]
 __drm_gem_object_put include/drm/drm_gem.h:370 [inline]
 drm_gem_object_put include/drm/drm_gem.h:383 [inline]
 drm_gem_object_handle_put_unlocked+0x3ac/0x420 drivers/gpu/drm/drm_gem.c:238
 drm_gem_object_release_handle+0xf9/0x1b0 drivers/gpu/drm/drm_gem.c:260
 idr_for_each+0x113/0x220 lib/idr.c:208
 drm_gem_release+0x22/0x30 drivers/gpu/drm/drm_gem.c:947
 drm_file_free.part.0+0x866/0xcb0 drivers/gpu/drm/drm_file.c:282
 drm_file_free drivers/gpu/drm/drm_file.c:251 [inline]
 drm_close_helper.isra.0+0x17d/0x1f0 drivers/gpu/drm/drm_file.c:309
 drm_release+0x1e6/0x530 drivers/gpu/drm/drm_file.c:494
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:140 [inline]
 exit_to_user_mode_prepare+0x195/0x1c0 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:242
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f3615f90c78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000002040 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: ffffffffffffffff RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffff71244ff R14: 00007f3615f919c0 R15: 000000000118cf4c