INFO: task kworker/u8:3:50 blocked for more than 143 seconds. Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:3 state:D stack:23536 pid:50 tgid:50 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:0) Call Trace: context_switch kernel/sched/core.c:5409 [inline] __schedule+0x1781/0x49d0 kernel/sched/core.c:6736 __schedule_loop kernel/sched/core.c:6813 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6828 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6885 __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:1498 [inline] __writeback_single_inode+0x69f/0xfd0 fs/fs-writeback.c:1715 writeback_sb_inodes+0x8e4/0x1220 fs/fs-writeback.c:1941 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2012 wb_writeback+0x45b/0xc70 fs/fs-writeback.c:2119 wb_check_background_flush fs/fs-writeback.c:2189 [inline] wb_do_writeback fs/fs-writeback.c:2277 [inline] wb_workfn+0xc33/0x1070 fs/fs-writeback.c:2304 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 Showing all locks held in the system: 1 lock held by khungtaskd/29: #0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #0: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 4 locks held by kworker/u8:3/50: #0: ffff88801aa8f148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline] #0: ffff88801aa8f148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335 #1: ffffc90000ba7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline] #1: ffffc90000ba7d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335 #2: ffff88802436c0e0 (&type->s_umount_key#44){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:561 #3: ffff88802436a0e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105 2 locks held by getty/4818: #0: ffff88802af830a0 (&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 5 locks held by syz-executor394/5064: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 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:222 [inline] watchdog+0xfb0/0xff0 kernel/hung_task.c:379 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 5064 Comm: syz-executor394 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024 RIP: 0010:PageTail include/linux/page-flags.h:286 [inline] RIP: 0010:folio_flags include/linux/page-flags.h:313 [inline] RIP: 0010:folio_test_referenced include/linux/page-flags.h:470 [inline] RIP: 0010:folio_mark_accessed+0x28/0x11b0 mm/swap.c:465 Code: 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 18 49 89 fd 48 bb 00 00 00 00 00 fc ff df e8 6c f4 c5 ff 4d 8d 75 08 <4d> 89 f7 49 c1 ef 03 41 80 3c 1f 00 74 08 4c 89 f7 e8 52 f5 25 00 RSP: 0018:ffffc9000411f090 EFLAGS: 00000293 RAX: ffffffff81ceffe4 RBX: dffffc0000000000 RCX: ffff8880795c8000 RDX: 0000000000000000 RSI: ffffffff8bfdfee0 RDI: ffffea0002ffd580 RBP: ffffc9000411f208 R08: ffffffff8217491a R09: 1ffffffff1f0c1bd R10: dffffc0000000000 R11: fffffbfff1f0c1be R12: ffff8880775b81d0 R13: ffffea0002ffd580 R14: ffffea0002ffd588 R15: 0000000000000200 FS: 000055557c3b5380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056011a2dcbd0 CR3: 0000000023efe000 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_ent_get fs/exfat/fatent.c:48 [inline] exfat_ent_get+0x14d/0x400 fs/exfat/fatent.c:97 __exfat_free_cluster+0x56f/0x990 fs/exfat/fatent.c:200 exfat_free_cluster+0x77/0xd0 fs/exfat/fatent.c:232 __exfat_truncate+0x747/0xa60 fs/exfat/file.c:236 exfat_truncate+0xe6/0x380 fs/exfat/file.c:260 exfat_setattr+0x1067/0x1930 fs/exfat/file.c:362 notify_change+0xb9d/0xe70 fs/attr.c:497 do_truncate+0x220/0x310 fs/open.c:65 handle_truncate fs/namei.c:3300 [inline] do_open fs/namei.c:3646 [inline] path_openat+0x29fe/0x3240 fs/namei.c:3799 do_filp_open+0x235/0x490 fs/namei.c:3826 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406 do_sys_open fs/open.c:1421 [inline] __do_sys_creat fs/open.c:1497 [inline] __se_sys_creat fs/open.c:1491 [inline] __x64_sys_creat+0x123/0x170 fs/open.c:1491 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f8c5e724a59 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd2ca4a678 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 0032656c69662f2e RCX: 00007f8c5e724a59 RDX: 00007f8c5e724a59 RSI: 0000000000000000 RDI: 0000000020000040 RBP: 00007f8c5e7995f0 R08: 000055557c3b64c0 R09: 000055557c3b64c0 R10: 00000000000014fa R11: 0000000000000246 R12: 00007ffd2ca4a6a0 R13: 00007ffd2ca4a8c8 R14: 431bde82d7b634db R15: 00007f8c5e76d03b INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.875 msecs