syzbot

INFO: task syz.2.59:5446 blocked for more than 151 seconds.
      Not tainted 6.11.0-syzkaller-11624-ge477dba5442c #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.59        state:D stack:23808 pid:5446  tgid:5446  ppid:5222   flags:0x00000000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5315 [inline]
 __schedule+0x1843/0x4ae0 kernel/sched/core.c:6675
 __schedule_loop kernel/sched/core.c:6752 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6767
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6824
 __mutex_lock_common kernel/locking/mutex.c:684 [inline]
 __mutex_lock+0x6a7/0xd70 kernel/locking/mutex.c:752
 pipe_release+0x48/0x320 fs/pipe.c:727
 __fput+0x23f/0x880 fs/file_table.c:431
 task_work_run+0x24f/0x310 kernel/task_work.c:228
 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:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdd4d77df39
RSP: 002b:00007ffdf8a440f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fdd4d937a80 RCX: 00007fdd4d77df39
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fdd4d937a80 R08: 0000000000000006 R09: 00007ffdf8a443ef
R10: 00000000005fd878 R11: 0000000000000246 R12: 000000000000febc
R13: 00007ffdf8a44200 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6701
2 locks held by syslogd/4654:
2 locks held by klogd/4661:
1 lock held by dhcpcd/4885:
4 locks held by dhcpcd/4886:
1 lock held by dhcpcd/4973:
2 locks held by getty/4979:
 #0: ffff88814bb910a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900031332f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a6/0x1e00 drivers/tty/n_tty.c:2211
1 lock held by syz.2.59/5446:
 #0: ffff88803083c468 (&pipe->mutex){+.+.}-{3:3}, at: pipe_release+0x48/0x320 fs/pipe.c:727
1 lock held by syz.2.59/5448:
 #0: ffff88803083c468 (&pipe->mutex){+.+.}-{3:3}, at: splice_file_to_pipe+0x2e/0x500 fs/splice.c:1292

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.11.0-syzkaller-11624-ge477dba5442c #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:223 [inline]
 watchdog+0xff4/0x1040 kernel/hung_task.c:379
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5217 Comm: syz-executor Not tainted 6.11.0-syzkaller-11624-ge477dba5442c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:lockdep_enabled kernel/locking/lockdep.c:122 [inline]
RIP: 0010:lock_acquire+0x144/0x550 kernel/locking/lockdep.c:5798
Code: 8b 05 40 75 92 7e 85 c0 0f 85 8f 01 00 00 65 48 8b 1c 25 80 d7 03 00 48 81 c3 dc 0a 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 e5 02 00 00 83 3b 00 0f 85 62 01 00 00 4c 8d bc 24 80
RSP: 0018:ffffc90003c27ac0 EFLAGS: 00000a07
RAX: 0000000000000000 RBX: ffff88802d4946dc RCX: ffffffff817014f4
RDX: 0000000000000000 RSI: ffffffff8c602040 RDI: ffffffff8c602000
RBP: ffffc90003c27c08 R08: ffffffff901bb66f R09: 1ffffffff20376cd
R10: dffffc0000000000 R11: fffffbfff20376ce R12: 1ffff92000784f60
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffffff81599856
FS:  0000555559bd2500(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcc8cad0c0 CR3: 0000000063768000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 group_send_sig_info+0xa3/0x310 kernel/signal.c:1444
 bpf_send_signal_common+0x2dd/0x430 kernel/trace/bpf_trace.c:857
 ____bpf_send_signal kernel/trace/bpf_trace.c:862 [inline]
 bpf_send_signal+0x19/0x30 kernel/trace/bpf_trace.c:860
 bpf_prog_7ba5217f62dcd359+0x41/0x45
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359
 trace_sys_enter+0x93/0xd0 include/trace/events/syscalls.h:18
 syscall_trace_enter+0xf8/0x150 kernel/entry/common.c:61
 syscall_enter_from_user_mode_work include/linux/entry-common.h:168 [inline]
 syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
 do_syscall_64+0xcc/0x230 arch/x86/entry/common.c:79
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f543198a9
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffdfaa40540 EFLAGS: 00000293 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 000000000000002e RCX: 00007f8f543198a9
RDX: 00007ffdfaa40540 RSI: 00007ffdfaa40670 RDI: 0000000000000011
RBP: 00007ffdfaa40b5c R08: 0000000000000000 R09: 7fffffffffffffff
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000032
R13: 000000000000ff59 R14: 000000000000ff4f R15: 00007ffdfaa40bb0
 </TASK>