INFO: task syz.8.2365:12036 blocked for more than 143 seconds.
      Tainted: G             L      syzkaller #0
      Blocked by coredump.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.2365      state:D stack:26152 pid:12036 tgid:12033 ppid:11368  task_flags:0x40054c flags:0x00080001
Call Trace:
 <TASK>
 __schedule+0x17d9/0x56c0
 schedule+0x164/0x2b0
 schedule_preempt_disabled+0x13/0x30
 __ww_mutex_lock+0x13a5/0x3350
 ww_mutex_lock+0x3f/0x1b0
 modeset_lock+0x2b4/0x630
 drm_atomic_get_plane_state+0x1ec/0x720
 drm_client_modeset_commit_atomic+0x227/0x7e0
 drm_client_modeset_commit_locked+0xcb/0x4d0
 drm_client_modeset_commit+0x4a/0x70
 __drm_fb_helper_restore_fbdev_mode_unlocked+0x9c/0x1c0
 drm_fbdev_client_restore+0x1b/0x30
 drm_client_dev_restore+0x14c/0x290
 drm_release+0x32d/0x400
 __fput+0x418/0xa50
 task_work_run+0x1d9/0x270
 do_exit+0x73a/0x2360
 do_group_exit+0x22d/0x2f0
 get_signal+0x121b/0x12c0
 arch_do_signal_or_restart+0xbb/0x860
 exit_to_user_mode_loop+0x104/0x730
 do_syscall_64+0x353/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f48e215e90e
RSP: 002b:00007f48e30fbb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: 0000000000000003 RBX: 00007f48e30fc6c0 RCX: 00007f48e215e90e
RDX: 0000000000000000 RSI: 00007f48e30fbc00 RDI: ffffffffffffff9c
RBP: 00007f48e30fbc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f48e2426038 R14: 00007f48e2425fa0 R15: 00007fff6151b598
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/0:1/10:
1 lock held by rcu_tasks_kthre/31:
 #0: ffffffff8eb5a5c8 (rcu_tasks.tasks_gp_mutex){+.+.}-{4:4}, at: rcu_tasks_one_gp+0xb2a/0xe20
1 lock held by khungtaskd/35:
 #0: ffffffff8eb59c20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
6 locks held by syz.8.2365/12036:
 #0: ffff8881072bc260 (&dev->clientlist_mutex){+.+.}-{4:4}, at: drm_client_dev_restore+0xb1/0x290
 #1: ffff888169cc7a70 (&helper->lock){+.+.}-{4:4}, at: __drm_fb_helper_restore_fbdev_mode_unlocked+0x7b/0x1c0
 #2: ffff8881072bc128 (&dev->master_mutex){+.+.}-{4:4}, at: drm_master_internal_acquire+0x20/0x80
 #3: ffff888169cc7890 (&client->modeset_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_locked+0x4c/0x4d0
 #4: ffffc90006b07730 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0x11a/0x7e0
 #5: ffffc90006b07758 (crtc_ww_class_mutex){+.+.}-{4:4}, at: drm_client_modeset_commit_atomic+0x11a/0x7e0
2 locks held by syz.0.3579/15602:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 Comm: khungtaskd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 nmi_cpu_backtrace+0x274/0x2d0
 nmi_trigger_cpumask_backtrace+0x17a/0x380
 sys_info+0x135/0x170
 watchdog+0xfd7/0x1030
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
