Kernel bug: INFO: task hung in do_coredump (3)
Subsystem: fs
Status: open

Crash report:
INFO: task syz-executor156:5855 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc4-syzkaller-00319-g05df91921da6 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor156 state:D stack:26984 pid:5855  tgid:5853  ppid:5852   task_flags:0x400740 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x2ff/0x4e0 kernel/sched/completion.c:116
 wait_for_common kernel/sched/completion.c:127 [inline]
 wait_for_completion_state+0x1c/0x40 kernel/sched/completion.c:264
 coredump_wait fs/coredump.c:504 [inline]
 do_coredump+0x8fa/0x4f10 fs/coredump.c:686
 get_signal+0x22e3/0x26d0 kernel/signal.c:3019
 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:111
 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+0x3f6/0x4c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8382be44a9
RSP: 002b:00007f83829fb218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 00000000000000ca RBX: 00007f8382c6e338 RCX: 00007f8382be44a9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f8382c6e33c
RBP: 00007f8382c6e330 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8382c3b074
R13: 000000000000006e R14: 00007fff94b16610 R15: 00007fff94b166f8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8e5c4940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e5c4940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e5c4940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770
2 locks held by getty/5591:
 #0: ffff8880377220a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
1 lock held by syz-executor156/5854:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-syzkaller-00319-g05df91921da6 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/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+0xf70/0x12c0 kernel/hung_task.c:470
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5854 Comm: syz-executor156 Not tainted 6.16.0-rc4-syzkaller-00319-g05df91921da6 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
RIP: 0010:prepare_to_wait_exclusive+0xbe/0x2b0 kernel/sched/wait.c:255
Code: b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 4c 8d 3d 00 00 00 00 80 3c 02 00 0f 85 78 01 00 00 4c 89 bb 88 17 00 00 66 90 <be> 04 00 00 00 65 48 8b 1d 5d f1 3b 12 48 8d 7b 18 e8 8c 45 8e 00
RSP: 0018:ffffc90003d3fb90 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff888023ba8000 RCX: ffffffff8198c6ec
RDX: 1ffff110047752f1 RSI: 0000000000000004 RDI: ffff888023ba9788
RBP: 0000000000000001 R08: 0000000000000001 R09: fffff520007a7f60
R10: 0000000000000003 R11: 0000000000000001 R12: ffff88807726e320
R13: 0000000000000202 R14: 0000000000000000 R15: ffffffff8194be9b
FS:  00007f8382b9d6c0(0000) GS:ffff888124715000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055abda79d168 CR3: 0000000071a0d000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 io_cqring_wait+0xc3e/0x18e0 io_uring/io_uring.c:2604
 __do_sys_io_uring_enter+0xef8/0x1630 io_uring/io_uring.c:3444
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8382be44a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8382b9d208 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007f8382c6e328 RCX: 00007f8382be44a9
RDX: 000000000000235c RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f8382c6e320 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 00007f8382c3b074
R13: 0000000000000003 R14: 0000000000003d1a R15: 0000200000000480
 </TASK>