INFO: task syz.4.256:8572 blocked for more than 143 seconds.
Not tainted 6.16.0-rc5-syzkaller-00038-g733923397fd9 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.256 state:D stack:25800 pid:8572 tgid:8560 ppid:7604 task_flags:0x400140 flags:0x00024004
Call Trace:
context_switch kernel/sched/core.c:5401 [inline]
__schedule+0x16a2/0x4cb0 kernel/sched/core.c:6790
__schedule_loop kernel/sched/core.c:6868 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6883
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6940
rwsem_down_write_slowpath+0xbec/0x1030 kernel/locking/rwsem.c:1176
__down_write_common kernel/locking/rwsem.c:1304 [inline]
__down_write kernel/locking/rwsem.c:1313 [inline]
down_write_nested+0x1b5/0x200 kernel/locking/rwsem.c:1694
vfs_rename+0x69a/0xec0 fs/namei.c:5108
do_renameat2+0x878/0xc50 fs/namei.c:5286
__do_sys_rename fs/namei.c:5333 [inline]
__se_sys_rename fs/namei.c:5331 [inline]
__x64_sys_rename+0x82/0x90 fs/namei.c:5331
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: 0033:0x7f1e6838e929
RSP: 002b:00007f1e6912b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f1e685b6080 RCX: 00007f1e6838e929
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000200000000780
RBP: 00007f1e68410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1e685b6080 R15: 00007ffe37566058
Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
#0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
#0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
1 lock held by khungtaskd/31:
#0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
5 locks held by kworker/u8:4/59:
2 locks held by kworker/u8:5/1323:
#0: ffff888147289948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
#0: ffff888147289948 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3321
#1: ffffc9000488fbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
#1: ffffc9000488fbc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3321
1 lock held by udevd/5205:
2 locks held by getty/5596:
#0: ffff88814c9d50a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by kworker/u8:8/6011:
2 locks held by udevd/8146:
3 locks held by udevd/8149:
5 locks held by syz.4.256/8561:
#0: ffff888051176428 (sb_writers#28){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
#1: ffff88805959be08 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: inode_lock_killable include/linux/fs.h:874 [inline]
#1: ffff88805959be08 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: do_truncate+0x171/0x220 fs/open.c:63
#2: ffff88805aa80a50 (&c->snapshot_create_lock){.+.+}-{4:4}, at: bch2_truncate+0xeb/0x200 fs/bcachefs/io_misc.c:295
#3: ffff88805aa84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:161 [inline]
#3: ffff88805aa84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:253 [inline]
#3: ffff88805aa84398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7f4/0xd80 fs/bcachefs/btree_iter.c:3505
#4: ffff88805aaa6710 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x542/0x1de0 fs/bcachefs/btree_update_interior.c:1211
6 locks held by syz.4.256/8572:
#0: ffff888051176428 (sb_writers#28){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
#1: ffff888051176738 (&type->s_vfs_rename_key#6){+.+.}-{4:4}, at: lock_rename fs/namei.c:3285 [inline]
#1: ffff888051176738 (&type->s_vfs_rename_key#6){+.+.}-{4:4}, at: do_renameat2+0x37f/0xc50 fs/namei.c:5232
#2: ffff88805959a740 (&sb->s_type->i_mutex_key#29/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
#2: ffff88805959a740 (&sb->s_type->i_mutex_key#29/1){+.+.}-{4:4}, at: lock_two_directories+0x141/0x220 fs/namei.c:3251
#3: ffff88805959aed8 (&sb->s_type->i_mutex_key#29/5){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:914 [inline]
#3: ffff88805959aed8 (&sb->s_type->i_mutex_key#29/5){+.+.}-{4:4}, at: lock_two_directories+0x16b/0x220 fs/namei.c:3252
#4: ffff88805959b670 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
#4: ffff88805959b670 (&sb->s_type->i_mutex_key#29){++++}-{4:4}, at: lock_two_nondirectories+0xe7/0x180 fs/inode.c:1233
#5: ffff88805959be08 (&sb->s_type->i_mutex_key#29/4){+.+.}-{4:4}, at: vfs_rename+0x69a/0xec0 fs/namei.c:5108
2 locks held by syz-executor/9546:
1 lock held by syz-executor/10005:
#0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
#0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
2 locks held by syz.4.458/10798:
1 lock held by dhcpcd-run-hook/10817:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc5-syzkaller-00038-g733923397fd9 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
watchdog+0xfee/0x1030 kernel/hung_task.c:470
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3f9/0x770 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: 10005 Comm: syz-executor Not tainted 6.16.0-rc5-syzkaller-00038-g733923397fd9 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409
Code: e8 ce c3 7f fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 9f 1b e1 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc9000421f4d0 EFLAGS: 00000002
RAX: 1ffffffff33b9400 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: ffffffff99dca730 R08: ffff888024d68237 R09: 1ffff110049ad046
R10: dffffc0000000000 R11: ffffffff85406130 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99dca4a0 R15: 0000000000000000
FS: 000055555f9d0500(0000) GS:ffff888125c4f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0c48db9000 CR3: 0000000076562000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:137 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline]
wait_for_lsr+0x19e/0x2f0 drivers/tty/serial/8250/8250_port.c:2094
fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3348 [inline]
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3371 [inline]
serial8250_console_write+0x134c/0x1ba0 drivers/tty/serial/8250/8250_port.c:3456
console_emit_next_record kernel/printk/printk.c:3138 [inline]
console_flush_all+0x728/0xc40 kernel/printk/printk.c:3226
__console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
console_unlock+0xc4/0x270 kernel/printk/printk.c:3325
vprintk_emit+0x5b7/0x7a0 kernel/printk/printk.c:2450
_printk+0xcf/0x120 kernel/printk/printk.c:2475
_btrfs_printk+0x562/0x5b0 fs/btrfs/messages.c:248
btrfs_put_super+0x69/0x80 fs/btrfs/super.c:73
generic_shutdown_super+0x135/0x2c0 fs/super.c:643
kill_anon_super+0x3b/0x70 fs/super.c:1282
btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2095
deactivate_locked_super+0xb9/0x130 fs/super.c:474
cleanup_mnt+0x425/0x4c0 fs/namespace.c:1417
task_work_run+0x1d4/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffbe1b8fc57
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fffacbdc1e8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000064 RCX: 00007ffbe1b8fc57
RDX: 0000000000000200 RSI: 0000000000000009 RDI: 00007fffacbdd390
RBP: 00007ffbe1c10925 R08: 000055555f9f366b R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000202 R12: 00007fffacbdd390
R13: 00007ffbe1c10925 R14: 000055555f9d04a8 R15: 00007fffacbde460