INFO: task syz.7.81:6734 blocked for more than 143 seconds.
      Not tainted 6.12.0-syzkaller-10553-gb86545e02e8c #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.81        state:D stack:27360 pid:6734  tgid:6679  ppid:6354   flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x17fb/0x4be0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6905
 rwsem_down_write_slowpath+0xeee/0x13b0 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1d7/0x220 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:818 [inline]
 vfs_unlink+0xe4/0x650 fs/namei.c:4512
 do_unlinkat+0x4ae/0x830 fs/namei.c:4587
 __do_sys_unlink fs/namei.c:4635 [inline]
 __se_sys_unlink fs/namei.c:4633 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4633
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fac87b80809
RSP: 002b:00007fac888ee058 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007fac87d46080 RCX: 00007fac87b80809
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0
RBP: 00007fac87bf393e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fac87d46080 R15: 00007ffe079dc098
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e93c560 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6744
2 locks held by getty/5603:
 #0: ffff8880315420a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
5 locks held by syz.7.81/6680:
 #0: ffff88807e8b6420 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff8880451088c8 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #1: ffff8880451088c8 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at: do_truncate+0x20c/0x310 fs/open.c:63
 #2: ffff88806cc00a38 (&c->snapshot_create_lock){.+.+}-{4:4}, at: bch2_truncate+0x166/0x2d0 fs/bcachefs/io_misc.c:292
 #3: ffff88806cc04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:158 [inline]
 #3: ffff88806cc04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: srcu_read_lock include/linux/srcu.h:249 [inline]
 #3: ffff88806cc04398 (&c->btree_trans_barrier){.+.+}-{0:0}, at: __bch2_trans_get+0x7e1/0xd30 fs/bcachefs/btree_iter.c:3228
 #4: ffff88806cc266d0 (&c->gc_lock){++++}-{4:4}, at: bch2_btree_update_start+0x682/0x14e0 fs/bcachefs/btree_update_interior.c:1197
3 locks held by syz.7.81/6734:
 #0: ffff88807e8b6420 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:515
 #1: ffff888045108148 (&sb->s_type->i_mutex_key#22/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:853 [inline]
 #1: ffff888045108148 (&sb->s_type->i_mutex_key#22/1){+.+.}-{4:4}, at: do_unlinkat+0x26a/0x830 fs/namei.c:4574
 #2: ffff8880451088c8 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline]
 #2: ffff8880451088c8 (&sb->s_type->i_mutex_key#22){++++}-{4:4}, at: vfs_unlink+0xe4/0x650 fs/namei.c:4512
1 lock held by syz-executor/8330:
 #0: ffff8880605500e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880605500e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880605500e0 (&type->s_umount_key#51){++++}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
1 lock held by syz.7.289/8907:
 #0: ffff8880605500e0 (&type->s_umount_key#51){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880605500e0 (&type->s_umount_key#51){++++}-{4:4}, at: super_lock+0x27c/0x400 fs/super.c:120
1 lock held by syz-executor/9266:
 #0: ffffffff8e941af8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:329 [inline]
 #0: ffffffff8e941af8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x451/0x830 kernel/rcu/tree_exp.h:976
2 locks held by syz.5.321/9547:
3 locks held by syz.0.326/9603:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-10553-gb86545e02e8c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:234 [inline]
 watchdog+0xffb/0x1040 kernel/hung_task.c:397
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9266 Comm: syz-executor Not tainted 6.12.0-syzkaller-10553-gb86545e02e8c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:debug_smp_processor_id+0x0/0x20 lib/smp_processor_id.c:59
Code: 55 9f 8e 48 89 de e8 7f 42 26 f9 e9 66 ff ff ff 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 <f3> 0f 1e fa 48 c7 c7 40 83 60 8c 48 c7 c6 80 83 60 8c eb 1c 66 2e
RSP: 0000:ffffc9000412f470 EFLAGS: 00000002
RAX: 0000000000000003 RBX: 00000087a6f4dcda RCX: ffffffff9a3f7903
RDX: 0000000000000087 RSI: ffffffff8c608380 RDI: 0000000000000001
RBP: 0000000000000532 R08: ffffffff854626d4 R09: 1ffff110049cc046
R10: dffffc0000000000 R11: ffffffff8bc6a810 R12: dffffc0000000000
R13: ffffffff9a437f70 R14: 0000000000000899 R15: 0000000000000000
FS:  000055558880f500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdbff351000 CR3: 000000004883e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 delay_tsc+0x6b/0xe0 arch/x86/lib/delay.c:90
 udelay include/asm-generic/delay.h:62 [inline]
 wait_for_lsr drivers/tty/serial/8250/8250_port.c:2093 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3334 [inline]
 serial8250_console_write+0x1328/0x1ed0 drivers/tty/serial/8250/8250_port.c:3412
 console_emit_next_record kernel/printk/printk.c:3122 [inline]
 console_flush_all+0x869/0xeb0 kernel/printk/printk.c:3210
 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
 console_unlock+0x14f/0x3b0 kernel/printk/printk.c:3309
 vprintk_emit+0x730/0xa10 kernel/printk/printk.c:2432
 _printk+0xd5/0x120 kernel/printk/printk.c:2457
 __ext4_msg+0x2db/0x2f0 fs/ext4/super.c:998
 ext4_put_super+0xc5/0xd50 fs/ext4/super.c:1303
 generic_shutdown_super+0x139/0x2d0 fs/super.c:642
 kill_block_super+0x44/0x90 fs/super.c:1710
 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7379
 deactivate_locked_super+0xc4/0x130 fs/super.c:473
 cleanup_mnt+0x41f/0x4b0 fs/namespace.c:1373
 task_work_run+0x24f/0x310 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f42c0181b37
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:00007ffc18bede68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f42c0181b37
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc18bedf20
RBP: 00007ffc18bedf20 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc18beefa0
R13: 00007f42c01f37dc R14: 000000000003eb1d R15: 00007ffc18beefe0
 </TASK>