syzbot

INFO: task syz-executor380:5075 blocked for more than 143 seconds.
      Not tainted 6.9.0-syzkaller-01049-g8815da98e06a #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor380 state:D stack:15344 pid:5075  tgid:5075  ppid:5072   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5409 [inline]
 __schedule+0x1796/0x4a00 kernel/sched/core.c:6746
 __schedule_loop kernel/sched/core.c:6823 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6838
 __closure_sync+0x259/0x2f0 lib/closure.c:135
 closure_sync include/linux/closure.h:194 [inline]
 __bch2_write+0x5458/0x5bd0 fs/bcachefs/io_write.c:1494
 bch2_write+0x947/0x15b0 fs/bcachefs/io_write.c:1620
 closure_queue include/linux/closure.h:257 [inline]
 closure_call include/linux/closure.h:390 [inline]
 bch2_dio_write_loop fs/bcachefs/fs-io-direct.c:531 [inline]
 bch2_direct_write+0x1a52/0x3050 fs/bcachefs/fs-io-direct.c:652
 bch2_write_iter+0x206/0x2840 fs/bcachefs/fs-io-buffered.c:1143
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa84/0xcb0 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4b7820edf9
RSP: 002b:00007ffc744fdc88 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4b7820edf9
RDX: 000000000f642e7e RSI: 0000000020000200 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000555500000000 R09: 0000555500000000
R10: 0000555500000000 R11: 0000000000000246 R12: 00000000000f4240
R13: 00007ffc744fdef8 R14: 0000000000000001 R15: 00007ffc744fdcc0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
2 locks held by getty/4830:
 #0: ffff88802b1770a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f162f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
2 locks held by syz-executor380/5075:
 #0: ffff888078f28420 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2855 [inline]
 #0: ffff888078f28420 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x233/0xcb0 fs/read_write.c:586
 #1: ffff88807eeb8150 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
 #1: ffff88807eeb8150 (&sb->s_type->i_mutex_key#16){+.+.}-{3:3}, at: bch2_direct_write+0x243/0x3050 fs/bcachefs/fs-io-direct.c:598

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

NMI backtrace for cpu 1
CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.9.0-syzkaller-01049-g8815da98e06a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfde/0x1020 kernel/hung_task.c:380
 kthread+0x2f0/0x390 kernel/kthread.c:388
 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 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112