INFO: task kworker/u8:7:1098 blocked for more than 143 seconds. Not tainted 6.9.0-rc7-syzkaller-00188-gba16c1cf11c9 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:7 state:D stack:23416 pid:1098 tgid:1098 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:1498 [inline] __writeback_single_inode+0x6b9/0x10b0 fs/fs-writeback.c:1715 writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2012 wb_writeback+0x46b/0xce0 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+0xc58/0x1090 fs/fs-writeback.c:2304 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:388 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: 1 lock held by khungtaskd/29: #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614 4 locks held by kworker/u8:7/1098: #0: ffff888019ae6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3242 [inline] #0: ffff888019ae6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348 #1: ffffc900048afd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline] #1: ffffc900048afd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348 #2: ffff8880245840e0 (&type->s_umount_key#44){.+.+}-{3:3}, at: super_trylock_shared+0x22/0xf0 fs/super.c:561 #3: ffff8880245860e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_write_inode+0x69/0x120 fs/exfat/inode.c:105 2 locks held by getty/4824: #0: ffff88802a6840a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002f0e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201 3 locks held by syz-executor425/5071: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.9.0-rc7-syzkaller-00188-gba16c1cf11c9 #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:388 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5071 Comm: syz-executor425 Not tainted 6.9.0-rc7-syzkaller-00188-gba16c1cf11c9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 RIP: 0010:__sanitizer_cov_trace_switch+0x90/0x120 kernel/kcov.c:340 Code: 85 d2 75 14 e9 9a 00 00 00 41 b8 05 00 00 00 4d 85 d2 0f 84 8b 00 00 00 4c 8b 4c 24 20 65 4c 8b 1c 25 80 d3 03 00 31 d2 eb 08 <48> ff c2 49 39 d2 74 71 4c 8b 74 d6 10 65 8b 05 d4 c5 6d 7e a9 00 RSP: 0018:ffffc900037c7660 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000005 RCX: ffffffff821a2849 RDX: 0000000000000002 RSI: ffffffff8e53f440 RDI: 0000000000000005 RBP: 1ffff920006f8f28 R08: 0000000000000005 R09: ffffffff82781de7 R10: 0000000000000003 R11: ffff88802b949e00 R12: dffffc0000000000 R13: 0000000000000005 R14: 00000000ffffffff R15: ffffc900037c7940 FS: 0000555572b84380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005557922177f0 CR3: 000000007b1a0000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: exfat_ent_get+0x1f7/0x400 fs/exfat/fatent.c:105 exfat_readdir fs/exfat/dir.c:187 [inline] exfat_iterate+0x1376/0x33e0 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: 0033:0x7fa73ca20063 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:00007ffc3fbf3b48 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 0000555572b8d730 RCX: 00007fa73ca20063 RDX: 0000000000008000 RSI: 0000555572b8d730 RDI: 0000000000000004 RBP: 0000555572b8d704 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000293 R12: ffffffffffffffb8 R13: 0000000000000010 R14: 0000555572b8d700 R15: 00007ffc3fbf5dc0 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.411 msecs