INFO: task syz.1.495:11075 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.495 state:D stack:25464 pid:11075 tgid:11071 ppid:9250 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5253 [inline]
__schedule+0x172e/0x4c90 kernel/sched/core.c:6861
__schedule_loop kernel/sched/core.c:6943 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6958
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+0x10e/0x160 kernel/kthread.c:1559
__alloc_workqueue+0x1466/0x1b70 kernel/workqueue.c:5795
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818
btrfs_init_workqueues+0x225/0x6c0 fs/btrfs/disk-io.c:1984
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3426
btrfs_fill_super fs/btrfs/super.c:987 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2094 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2128
vfs_get_tree+0x92/0x2a0 fs/super.c:1759
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2bc9e40eea
RSP: 002b:00007f2bc80a5e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2bc80a5ef0 RCX: 00007f2bc9e40eea
RDX: 00002000000055c0 RSI: 0000200000000380 RDI: 00007f2bc80a5eb0
RBP: 00002000000055c0 R08: 00007f2bc80a5ef0 R09: 0000000000000088
R10: 0000000000000088 R11: 0000000000000246 R12: 0000200000000380
R13: 00007f2bc80a5eb0 R14: 00000000000055ae R15: 0000200000000080
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5ae320 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:12/1504:
#0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813ff69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3346
#1: ffffc900059d7b80 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc900059d7b80 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3346
7 locks held by kworker/u8:14/1553:
2 locks held by udevd/5179:
2 locks held by getty/5567:
#0: ffff88823bf3e8a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
10 locks held by syz-executor/9483:
2 locks held by udevd/9629:
1 lock held by syz.1.495/11075:
#0: ffff888065bf00d0 (&type->s_umount_key#50/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
2 locks held by syz.4.749/14197:
#0: ffff88803d322d90 (&sb->s_type->i_mutex_key#27){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
#0: ffff88803d322d90 (&sb->s_type->i_mutex_key#27){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1874
#1: ffff88803569c0d8 (&sbi->s_lock){+.+.}-{4:4}, at: exfat_lookup+0x136/0x17b0 fs/exfat/namei.c:730
2 locks held by syz.2.752/14199:
1 lock held by dhcpcd-run-hook/14204:
#0: ffff8880b8836b50 ((crngs.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#0: ffff8880b8836b50 ((crngs.lock)){+.+.}-{3:3}, at: crng_make_state+0x163/0x5e0 drivers/char/random.c:368
=============================================
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 10/25/2025
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:332 [inline]
watchdog+0xf3c/0xf80 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x52d/0xa60 arch/x86/kernel/process.c:158
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: 14199 Comm: syz.2.752 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__this_cpu_preempt_check+0x0/0x20 lib/smp_processor_id.c:63
Code: 56 1e 72 f6 eb a7 e8 bf e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 89 fe 48 c7 c7 80 7e 3e 8b e9 bd fe ff ff cc cc cc
RSP: 0018:ffffc900178df378 EFLAGS: 00000092
RAX: 0000000000000001 RBX: 0000000000000000 RCX: bbfae0e6eddfbed0
RDX: 0000000027512900 RSI: 00000000d18ffb14 RDI: ffffffff8cfbaf1f
RBP: ffffffff8ac269a0 R08: ffffffff8ac269a0 R09: ffff8880b8942758
R10: dffffc0000000000 R11: fffffbfff1db286f R12: 0000000000000000
R13: ffff8880b8942758 R14: 0000000000000001 R15: 0000000000000046
FS: 00007fb88dfe66c0(0000) GS:ffff888126e88000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2e61aff8 CR3: 0000000051690000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
lock_acquire+0x127/0x340 kernel/locking/lockdep.c:5870
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417
spin_unlock include/linux/spinlock_rt.h:105 [inline]
rmqueue_pcplist mm/page_alloc.c:3305 [inline]
rmqueue mm/page_alloc.c:3335 [inline]
get_page_from_freelist+0x9fa/0x2960 mm/page_alloc.c:3876
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5178
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
folio_alloc_mpol_noprof+0x39/0xe0 mm/mempolicy.c:2435
shmem_alloc_folio mm/shmem.c:1870 [inline]
shmem_alloc_and_add_folio mm/shmem.c:1912 [inline]
shmem_get_folio_gfp+0x633/0x1a70 mm/shmem.c:2535
shmem_get_folio mm/shmem.c:2641 [inline]
shmem_write_begin+0xef/0x2a0 mm/shmem.c:3291
generic_perform_write+0x29d/0x8c0 mm/filemap.c:4300
shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3466
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d5/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb88fd7e1ff
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007fb88dfe5df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fb88fd7e1ff
RDX: 0000000001000000 RSI: 00007fb885bc6000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005598
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fb88dfe5ef0 R14: 00007fb88dfe5eb0 R15: 00007fb885bc6000