syzbot

INFO: task kworker/u4:9:2429 blocked for more than 143 seconds.
      Not tainted 6.8.0-rc3-syzkaller-00215-ge6f39a90de92 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:9    state:D stack:20216 pid:2429  tgid:2429  ppid:2      flags:0x00004000
Workqueue: writeback wb_workfn (flush-7:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0x177f/0x49a0 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6802 [inline]
 schedule+0x149/0x260 kernel/sched/core.c:6817
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6874
 rwsem_down_write_slowpath+0xeea/0x13b0 kernel/locking/rwsem.c:1178
 __down_write_common+0x1ae/0x200 kernel/locking/rwsem.c:1306
 f2fs_down_write fs/f2fs/f2fs.h:2138 [inline]
 f2fs_balance_fs+0x500/0x730 fs/f2fs/segment.c:437
 f2fs_write_inode+0x3f0/0x470 fs/f2fs/inode.c:794
 write_inode fs/fs-writeback.c:1473 [inline]
 __writeback_single_inode+0x69f/0xfd0 fs/fs-writeback.c:1690
 writeback_sb_inodes+0x8e3/0x1220 fs/fs-writeback.c:1916
 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:1987
 wb_writeback+0x461/0xc80 fs/fs-writeback.c:2094
 wb_check_background_flush fs/fs-writeback.c:2164 [inline]
 wb_do_writeback fs/fs-writeback.c:2252 [inline]
 wb_workfn+0xc33/0xfb0 fs/fs-writeback.c:2279
 process_one_work kernel/workqueue.c:2633 [inline]
 process_scheduled_works+0x913/0x1420 kernel/workqueue.c:2706
 worker_thread+0xa5f/0x1000 kernel/workqueue.c:2787
 kthread+0x2ef/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8e130ae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8e130ae0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8e130ae0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
4 locks held by kworker/u4:9/2429:
 #0: ffff888018ee1d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
 #0: ffff888018ee1d38 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
 #1: ffffc90009ddfd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:2608 [inline]
 #1: ffffc90009ddfd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x825/0x1420 kernel/workqueue.c:2706
 #2: ffff88802c72c0e0 (&type->s_umount_key#43){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:566
 #3: ffff888078bf92a8 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2138 [inline]
 #3: ffff888078bf92a8 (&sbi->gc_lock){+.+.}-{3:3}, at: f2fs_balance_fs+0x500/0x730 fs/f2fs/segment.c:437
1 lock held by syslogd/4493:
 #0: ffff8880b953c918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559
2 locks held by getty/4809:
 #0: ffff88802ff920a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f162f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b4/0x1e10 drivers/tty/n_tty.c:2201
6 locks held by syz-executor242/5074:

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

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc3-syzkaller-00215-ge6f39a90de92 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xfaf/0xff0 kernel/hung_task.c:379
 kthread+0x2ef/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 22 Comm: ksoftirqd/1 Not tainted 6.8.0-rc3-syzkaller-00215-ge6f39a90de92 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:free_unref_page_commit+0xc1/0x1140 mm/page_alloc.c:2440
Code: 04 21 84 c0 4c 89 44 24 40 0f 85 59 08 00 00 c7 84 24 a0 00 00 00 00 00 00 00 48 8d 5a 55 48 89 d8 48 c1 e8 03 42 0f b6 04 20 <84> c0 4c 89 6c 24 30 0f 85 64 08 00 00 d0 2b 41 83 f8 20 0f 83 3b
RSP: 0018:ffffc900001c78c0 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff8880b9542815 RCX: ffffc900001c7903
RDX: ffff8880b95427c0 RSI: ffff8880b95427c0 RDI: ffff88813fffa740
RBP: ffffc900001c79c8 R08: 0000000000000000 R09: 1ffffffff258a484
R10: dffffc0000000000 R11: fffffbfff258a485 R12: dffffc0000000000
R13: ffffea0001de7740 R14: 1ffff92000038f28 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ba051976d0 CR3: 000000001e5ba000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 free_unref_page+0x17c/0x3f0 mm/page_alloc.c:2509
 rcu_do_batch kernel/rcu/tree.c:2190 [inline]
 rcu_core+0xd76/0x1810 kernel/rcu/tree.c:2465
 __do_softirq+0x2bb/0x942 kernel/softirq.c:553
 run_ksoftirqd+0xc5/0x130 kernel/softirq.c:921
 smpboot_thread_fn+0x543/0xa30 kernel/smpboot.c:164
 kthread+0x2ef/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.759 msecs