INFO: task syz.3.191:9928 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.191 state:D stack:24840 pid:9928 tgid:9925 ppid:6333 task_flags:0x400140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:100 [inline] __wait_for_common kernel/sched/completion.c:121 [inline] wait_for_common kernel/sched/completion.c:132 [inline] wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153 kthread_flush_worker+0x1c6/0x240 kernel/kthread.c:1564 __alloc_workqueue+0x1470/0x1b70 kernel/workqueue.c:5795 alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818 btrfs_alloc_ordered_workqueue+0x1c3/0x290 fs/btrfs/async-thread.c:140 btrfs_init_workqueues+0x3f0/0x6c0 fs/btrfs/disk-io.c:1997 open_ctree+0x13bf/0x3cc0 fs/btrfs/disk-io.c:3425 btrfs_fill_super fs/btrfs/super.c:987 [inline] btrfs_get_tree_super fs/btrfs/super.c:1952 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2089 [inline] btrfs_get_tree+0xf55/0x1820 fs/btrfs/super.c:2123 vfs_get_tree+0x92/0x2b0 fs/super.c:1752 do_new_mount+0x2a2/0xa30 fs/namespace.c:3750 do_mount fs/namespace.c:4078 [inline] __do_sys_mount fs/namespace.c:4278 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4255 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f42dffefeba RSP: 002b:00007f42df265e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f42df265ef0 RCX: 00007f42dffefeba RDX: 00000000200055c0 RSI: 0000000020005600 RDI: 00007f42df265eb0 RBP: 00000000200055c0 R08: 00007f42df265ef0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020005600 R13: 00007f42df265eb0 R14: 00000000000055a1 R15: 0000000020005640 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8d3a97c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d3a97c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d3a97c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:5/70: #0: ffff888019481938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888019481938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc9000154fbc0 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc9000154fbc0 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 2 locks held by kworker/u8:9/1283: #0: ffff888019481938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff888019481938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc900051e7bc0 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc900051e7bc0 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 2 locks held by getty/5581: #0: ffff88823bf2e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222 1 lock held by udevd/6584: 4 locks held by udevd/6606: 2 locks held by udevd/7594: 1 lock held by syz.3.191/9928: #0: ffff8880342100d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x204/0x990 fs/super.c:345 2 locks held by kworker/u8:0/11360: 2 locks held by syz.5.361/13095: 1 lock held by udevadm/13111: 2 locks held by udevadm/13112: 2 locks held by syz.4.362/13129: 4 locks held by syz.0.363/13131: 2 locks held by syz.1.365/13134: ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 13131 Comm: syz.0.363 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0033:0x7f758c4318c8 Code: 9e fd ff ff 41 8d 34 04 49 8b 47 10 48 39 f0 72 6e 48 63 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 RSP: 002b:00007f758b7ed4a0 EFLAGS: 00000206 RAX: 000000000075dc6b RBX: 00007f758b7ed540 RCX: 00000000000000fc RDX: 0000000000000055 RSI: 0000000000000001 RDI: 00007f758b7ed5e0 RBP: 0000000000000102 R08: 00007f75833ce000 R09: 0000000000000000 R10: 0000000000000000 R11: 00007f758b7ed550 R12: 0000000000000001 R13: 00007f758c5f5fc0 R14: 0000000000000000 R15: 00007f758b7ed5e0 FS: 00007f758b7ee6c0 GS: 0000000000000000