INFO: task syz.6.1364:18276 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1364 state:D stack:25624 pid:18276 tgid:18275 ppid:7125 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x1485/0x1b80 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5820
btrfs_init_workqueues+0x3de/0x680 fs/btrfs/disk-io.c:1992
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3411
btrfs_fill_super fs/btrfs/super.c:981 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1944 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2121
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
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+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd0ba720eea
RSP: 002b:00007fd0b897de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd0b897def0 RCX: 00007fd0ba720eea
RDX: 00002000000055c0 RSI: 0000200000000000 RDI: 00007fd0b897deb0
RBP: 00002000000055c0 R08: 00007fd0b897def0 R09: 000000000300000a
R10: 000000000300000a R11: 0000000000000246 R12: 0000200000000000
R13: 00007fd0b897deb0 R14: 00000000000055a3 R15: 0000200000000080
Showing all locks held in the system:
1 lock held by kthreadd/2:
1 lock held by khungtaskd/38:
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5175:
2 locks held by getty/5565:
#0: ffff88803466a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211
2 locks held by kworker/0:3/5799:
1 lock held by udevd/7255:
5 locks held by syz-executor/13598:
#0: ffff88802adef448 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a7/0x4a0 mm/mmap_lock.c:259
#1: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#1: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#1: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x200 mm/pgtable-generic.c:288
#2: ffff88805bab7b98 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#2: ffff88805bab7b98 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:403
#3: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#3: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#3: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#3: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1c1/0x3e0 kernel/locking/spinlock_rt.c:57
#4: ffff8880b8833cd0 ((lock)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#4: ffff8880b8833cd0 ((lock)#2){+.+.}-{3:3}, at: __folio_batch_add_and_move+0x284/0xa90 mm/swap.c:-1
3 locks held by udevd/14839:
#0: ffff8880327e6480 (sb_writers#5){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline]
#0: ffff8880327e6480 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682
#1: ffff88805cd49c78 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff88805cd49c78 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: shmem_file_write_iter+0x82/0x120 mm/shmem.c:3480
#2: ffff8880b8833cd0 ((lock)#2){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#2: ffff8880b8833cd0 ((lock)#2){+.+.}-{3:3}, at: __folio_batch_add_and_move+0x284/0xa90 mm/swap.c:-1
1 lock held by syz.6.1364/18276:
#0: ffff8880396000d0 (&type->s_umount_key#66/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
3 locks held by syz-executor/18537:
1 lock held by syz.3.1604/20544:
#0: ffff888040eac0d0 (&type->s_umount_key#66/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
4 locks held by syz.7.1608/20567:
2 locks held by syz.8.1612/20572:
=============================================
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+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 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]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 20590 Comm: syz-executor Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:mark_usage kernel/locking/lockdep.c:4674 [inline]
RIP: 0010:__lock_acquire+0x6a6/0x2cf0 kernel/locking/lockdep.c:5191
Code: 08 4c 89 ee ba 04 00 00 00 e8 96 44 00 00 85 c0 0f 84 99 0d 00 00 41 8b 45 20 a9 00 00 18 00 0f 84 bc 00 00 00 4c 8b 74 24 08 <4c> 89 f7 4c 89 ee ba 08 00 00 00 e8 6a 44 00 00 31 ed 85 c0 0f 84
RSP: 0000:ffffc9000567f928 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff88807fa93c80 RCX: ffffffff925c9e50
RDX: 0000000000000006 RSI: ffff88807fa94860 RDI: ffff88807fa93c80
RBP: 0000000000000000 R08: ffffffff82141f7d R09: ffffffff8d6ce700
R10: dffffc0000000000 R11: fffff94000331a07 R12: 0000000000000118
R13: ffff88807fa94860 R14: ffff88807fa93c80 R15: ffff88807fa94810
FS: 0000555556c51500(0000) GS:ffff888126dee000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3d57915e93 CR3: 00000000605c4000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868
fs_reclaim_acquire+0x99/0x100 mm/page_alloc.c:4318
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4904 [inline]
slab_alloc_node mm/slub.c:5239 [inline]
kmem_cache_alloc_noprof+0x40/0x6c0 mm/slub.c:5270
ptlock_alloc+0x20/0x70 mm/memory.c:7377
ptlock_init include/linux/mm.h:3280 [inline]
pagetable_pte_ctor include/linux/mm.h:3334 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline]
pte_alloc_one+0x7e/0x380 arch/x86/mm/pgtable.c:18
do_fault_around mm/memory.c:5707 [inline]
do_read_fault mm/memory.c:5746 [inline]
do_fault mm/memory.c:5889 [inline]
do_pte_missing+0x147b/0x27a0 mm/memory.c:4401
handle_pte_fault mm/memory.c:6273 [inline]
__handle_mm_fault mm/memory.c:6411 [inline]
handle_mm_fault+0xcc1/0x1330 mm/memory.c:6580
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x71/0xd0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f3d57915e93
Code: Unable to access opcode bytes at 0x7f3d57915e69.
RSP: 002b:00007ffd55de2658 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f3d57915e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000555556c517d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 000000000012b7ed R15: 00007ffd55de27f0