INFO: task kworker/u8:1:12 blocked for more than 143 seconds. Not tainted 6.9.0-syzkaller-03117-gb850dc206a57 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:1 state:D stack:19384 pid:12 tgid:12 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0x1796/0x4a00 kernel/sched/core.c:6746 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6838 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x6a4/0xd70 kernel/locking/mutex.c:752 exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105 write_inode fs/fs-writeback.c:1497 [inline] __writeback_single_inode+0x6b9/0x10b0 fs/fs-writeback.c:1716 writeback_sb_inodes+0x99c/0x1380 fs/fs-writeback.c:1947 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2018 wb_writeback+0x495/0xd40 fs/fs-writeback.c:2129 wb_check_background_flush fs/fs-writeback.c:2199 [inline] wb_do_writeback fs/fs-writeback.c:2287 [inline] wb_workfn+0xc58/0x1090 fs/fs-writeback.c:2314 process_one_work kernel/workqueue.c:3267 [inline] process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3348 worker_thread+0x86d/0xd70 kernel/workqueue.c:3429 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Showing all locks held in the system: 4 locks held by kworker/u8:1/12: #0: ffff88801be8f148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3242 [inline] #0: ffff88801be8f148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348 #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline] #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348 #2: ffff8880247c80e0 (&type->s_umount_key#44){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:561 #3: ffff8880796560e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105 1 lock held by khungtaskd/30: #0: ffffffff8e3360e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e3360e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #0: ffffffff8e3360e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 2 locks held by getty/4832: #0: ffff88802a92e0a0 (&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+0x6b5/0x1e10 drivers/tty/n_tty.c:2201 3 locks held by syz-executor122/5079: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 30 Comm: khungtaskd Not tainted 6.9.0-syzkaller-03117-gb850dc206a57 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 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:223 [inline] watchdog+0xfde/0x1020 kernel/hung_task.c:380 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5079 Comm: syz-executor122 Not tainted 6.9.0-syzkaller-03117-gb850dc206a57 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:206 [inline] RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:238 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:folio_test_idle include/linux/page-flags.h:635 [inline] RIP: 0010:folio_mark_accessed+0x6bb/0x11b0 mm/swap.c:502 Code: e6 01 31 ff e8 46 7a c5 ff 48 83 e3 01 0f 85 b8 02 00 00 0f 1f 44 00 00 e8 52 75 c5 ff 4c 89 ef be 08 00 00 00 e8 85 f0 26 00 <48> b8 00 00 00 00 00 fc ff df 41 80 3c 04 00 74 08 4c 89 ef e8 fc RSP: 0018:ffffc9000333f350 EFLAGS: 00000256 RAX: ffffffff81d0cd01 RBX: 0000000000000000 RCX: ffffffff81d0cd3b RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffea0001e83540 RBP: 0000000000000100 R08: ffffea0001e83547 R09: 1ffffd40003d06a8 R10: dffffc0000000000 R11: fffff940003d06a9 R12: 1ffffd40003d06a8 R13: ffffea0001e83540 R14: ffffea0001e83548 R15: 1ffffd40003d06a9 FS: 000055557ad68380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056211b30f600 CR3: 000000001114c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __find_get_block+0x540/0x10d0 fs/buffer.c:1405 bdev_getblk+0x38/0x610 fs/buffer.c:1423 __bread_gfp+0xac/0x430 fs/buffer.c:1474 sb_bread include/linux/buffer_head.h:321 [inline] exfat_get_dentry+0x53b/0x730 fs/exfat/dir.c:691 exfat_readdir fs/exfat/dir.c:121 [inline] exfat_iterate+0xbd7/0x33e0 fs/exfat/dir.c:261 wrap_directory_iterator+0x94/0xe0 fs/readdir.c:67 iterate_dir+0x539/0x6f0 fs/readdir.c:110 __do_sys_getdents64 fs/readdir.c:409 [inline] __se_sys_getdents64+0x20d/0x4f0 fs/readdir.c:394 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f087378a063 Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 b2 48 fb ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 b8 ff ff ff f7 d8 RSP: 002b:00007ffe95c9d2f8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 000055557ad71730 RCX: 00007f087378a063 RDX: 0000000000008000 RSI: 000055557ad71730 RDI: 0000000000000004 RBP: 000055557ad71704 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000293 R12: ffffffffffffffb8 R13: 0000000000000010 R14: 000055557ad71700 R15: 00007ffe95c9f570 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.614 msecs