INFO: task kworker/u8:1:12 blocked for more than 143 seconds. Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:1 state:D stack:19192 pid:12 tgid:12 ppid:2 flags:0x00004000 Workqueue: writeback wb_workfn (flush-7:4) Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905 __mutex_lock_common kernel/locking/mutex.c:665 [inline] __mutex_lock+0x7e7/0xee0 kernel/locking/mutex.c:735 exfat_write_inode+0xe5/0x1a0 fs/exfat/inode.c:108 write_inode fs/fs-writeback.c:1525 [inline] __writeback_single_inode+0x708/0x10d0 fs/fs-writeback.c:1745 writeback_sb_inodes+0x820/0x1360 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x11b/0x260 fs/fs-writeback.c:2047 wb_writeback+0x427/0xb80 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xb94/0x1080 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310 worker_thread+0x870/0xd30 kernel/workqueue.c:3391 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: ffff8881436f2948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3204 [inline] #0: ffff8881436f2948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x93b/0x1840 kernel/workqueue.c:3310 #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3205 [inline] #1: ffffc90000117d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x976/0x1840 kernel/workqueue.c:3310 #2: ffff888034e000e0 (&type->s_umount_key#52){++++}-{4:4}, at: super_trylock_shared+0x22/0xf0 fs/super.c:562 #3: ffff888059a220e8 (&sbi->s_lock){+.+.}-{4:4}, at: exfat_write_inode+0xe5/0x1a0 fs/exfat/inode.c:108 1 lock held by khungtaskd/30: #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline] #0: ffffffff8e937ae0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744 7 locks held by kworker/u8:5/151: 3 locks held by kworker/u8:6/2200: 2 locks held by kworker/u8:9/3536: 2 locks held by getty/5579: #0: ffff88803548a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90002fde2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211 3 locks held by syz-executor/5820: 1 lock held by udevd/5821: 2 locks held by syz-executor/8018: 2 locks held by syz.1.330/9391: #0: ffff888034e000e0 (&type->s_umount_key#52){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888034e000e0 (&type->s_umount_key#52){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff888142bdc7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888142bdc7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x26e/0xb50 fs/fs-writeback.c:2819 2 locks held by kworker/u8:11/9535: 2 locks held by syz.3.350/9604: #0: ffff888034e000e0 (&type->s_umount_key#52){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff888034e000e0 (&type->s_umount_key#52){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120 #1: ffff888142bdc7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline] #1: ffff888142bdc7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x26e/0xb50 fs/fs-writeback.c:2819 2 locks held by syz.5.418/10362: #0: ffff888057f080e0 (&type->s_umount_key#65/1){+.+.}-{4:4}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e93cec0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:4565 2 locks held by syz.4.423/10393: #0: ffff888034d9a0e0 (&type->s_umount_key#89/1){+.+.}-{4:4}, at: alloc_super+0x221/0x9d0 fs/super.c:344 #1: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline] #1: ffffffff8e93cff8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976 2 locks held by syz.4.423/10405: 3 locks held by syz.7.425/10392: 2 locks held by syz.0.426/10400: 1 lock held by sed/10407: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 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:162 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline] watchdog+0xff6/0x1040 kernel/hung_task.c:397 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10405 Comm: syz.4.423 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0033:0x7fb09ae48c4b Code: cd 48 01 c1 49 39 4f 08 72 4c 8d 4d ff 85 ed 74 33 66 0f 1f 44 00 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 47 0f b6 0c 08 <45> 84 c9 74 08 45 88 0c 00 49 8b 47 10 48 83 c0 01 49 89 47 10 83 RSP: 002b:00007fb098dd44a0 EFLAGS: 00000202 RAX: 000000000034ed1b RBX: 00007fb098dd4540 RCX: 0000000000000074 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007fb098dd45e0 RBP: 0000000000000102 R08: 00007fb090800000 R09: 0000000000000000 R10: 0000000000000000 R11: 00007fb098dd4550 R12: 0000000000000001 R13: 00007fb09b019040 R14: 0000000000000000 R15: 00007fb098dd45e0 FS: 00007fb098dd56c0 GS: 0000000000000000