INFO: task syz.5.1327:18550 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.5.1327 state:D stack:25704 pid:18550 tgid:18548 ppid:6384 task_flags:0x400140 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 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+0x146b/0x1b70 kernel/workqueue.c:5763 alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5786 btrfs_alloc_workqueue+0x1ec/0x2d0 fs/btrfs/async-thread.c:112 btrfs_init_workqueues+0x2c4/0x6c0 fs/btrfs/disk-io.c:1986 open_ctree+0x11ef/0x3a10 fs/btrfs/disk-io.c:3424 btrfs_fill_super fs/btrfs/super.c:980 [inline] btrfs_get_tree_super fs/btrfs/super.c:1943 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2080 [inline] btrfs_get_tree+0xf55/0x1820 fs/btrfs/super.c:2114 vfs_get_tree+0x8f/0x2b0 fs/super.c:1815 do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x317/0x410 fs/namespace.c:4324 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: 0033:0x7fac8127034a RSP: 002b:00007fac7f4cde68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fac7f4cdef0 RCX: 00007fac8127034a RDX: 0000200000000000 RSI: 00002000000015c0 RDI: 00007fac7f4cdeb0 RBP: 0000200000000000 R08: 00007fac7f4cdef0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000015c0 R13: 00007fac7f4cdeb0 R14: 000000000000559e R15: 0000200000001600 Showing all locks held in the system: 2 locks held by kworker/u8:0/12: 1 lock held by khungtaskd/38: #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:11/3506: 2 locks held by getty/5599: #0: ffff88823bf2a8a0 (&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 3 locks held by syz-executor/5839: 2 locks held by syz-executor/5846: 1 lock held by udevd/5991: 1 lock held by syz.5.1327/18550: #0: ffff88804a55c0d0 (&type->s_umount_key#69/1){+.+.}-{4:4}, at: alloc_super+0x204/0x990 fs/super.c:345 1 lock held by syz.7.1518/20213: #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.7.1518/20216: #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.7.1518/20217: #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88805e0a80d0 (&type->s_umount_key#71){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.8.1545/20360: #0: ffff88805ea620d0 (&type->s_umount_key#59/1){+.+.}-{4:4}, at: alloc_super+0x204/0x990 fs/super.c:345 3 locks held by syz.4.1547/20365: 4 locks held by syz-executor/20366: ============================================= NMI backtrace for cpu 1 CPU: 1 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+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20379 Comm: syz.2.1550 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0033:0x7f881fe70c60 Code: 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> e9 01 73 d3 41 81 fe 00 01 00 00 0f 85 ce fe ff ff e9 10 ff ff RSP: 002b:00007f881e20d4a0 EFLAGS: 00000202 RAX: 000000000031bb01 RBX: 00007f881e20d540 RCX: 000000000000001a RDX: 0000000000000000 RSI: 0000000000000001 RDI: 00007f881e20d5e0 RBP: 0000000000000102 R08: 00007f8815dee000 R09: 0000000000000000 R10: 0000000000000000 R11: 00007f881e20d550 R12: 0000000000000001 R13: 00007f882004da00 R14: 0000000000000000 R15: 00007f881e20d5e0 FS: 00007f881e20e6c0 GS: 0000000000000000