syzbot

INFO: task dhcpcd:3173 blocked for more than 143 seconds.
      Not tainted 5.15.149-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:23544 pid: 3173 ppid:     1 flags:0x00004202
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 wait_for_unix_gc+0x14e/0x210 net/unix/garbage.c:201
 unix_dgram_sendmsg+0x143/0x2090 net/unix/af_unix.c:1771
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x39b/0x530 net/socket.c:1079
 call_write_iter include/linux/fs.h:2146 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0xacf/0xe50 fs/read_write.c:594
 ksys_write+0x1a2/0x2c0 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc5e5c02bf2
RSP: 002b:00007ffc386dc8b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000562ca6f7bcf0 RCX: 00007fc5e5c02bf2
RDX: 0000000000000047 RSI: 00007ffc386dc8d0 RDI: 0000000000000005
RBP: 00007ffc386dc8d0 R08: 0000000000000008 R09: 0000000000000036
R10: 0000000000000000 R11: 0000000000000246 R12: 0000562ca65c9efc
R13: 00007ffc386dcd00 R14: 0000562ca700f380 R15: 0000000000000001
 </TASK>
INFO: task syz-executor127:6884 blocked for more than 143 seconds.
      Not tainted 5.15.149-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor127 state:D stack:26624 pid: 6884 ppid:  3515 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 wait_for_unix_gc+0x14e/0x210 net/unix/garbage.c:201
 unix_stream_sendmsg+0xc3/0x1070 net/unix/af_unix.c:2035
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2431
 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2485
 __sys_sendmsg net/socket.c:2514 [inline]
 __do_sys_sendmsg net/socket.c:2523 [inline]
 __se_sys_sendmsg+0x19a/0x260 net/socket.c:2521
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fdc175b7bb9
RSP: 002b:00007ffcd95edba8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdc175b7bb9
RDX: 000000000400c8c1 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000002559f R08: 0000000000000006 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcd95edbbc
R13: 431bde82d7b634db R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c91f720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by dhcpcd/3174:
2 locks held by getty/3260:
 #0: ffff88802495e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002bab2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3174 Comm: dhcpcd Not tainted 5.15.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0xc/0x60 kernel/kcov.c:197
Code: 89 fb e8 17 00 00 00 48 8b 3d 88 86 63 0c 48 89 de 5b e9 87 e1 48 00 cc cc cc cc cc cc cc 48 8b 04 24 65 48 8b 0d d4 39 82 7e <65> 8b 15 d5 39 82 7e f7 c2 00 01 ff 00 74 11 f7 c2 00 01 00 00 74
RSP: 0018:ffffc90003157af8 EFLAGS: 00000246
RAX: ffffffff88f53310 RBX: ffff888079906770 RCX: ffff88807e1d3b80
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffffc90003157c70 R08: ffffffff882d0af3 R09: ffffed100377dbd4
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff1100f320cee
R13: ffffc90003157b60 R14: 0000000000000000 R15: ffffffff8dad5720
FS:  00007fc5e5b38740(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc5e5ce4580 CR3: 000000001b837000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unix_gc+0x10e0/0x13b0 net/unix/garbage.c:320
 unix_release_sock+0x91c/0xaa0 net/unix/af_unix.c:607
 unix_release+0x88/0xc0 net/unix/af_unix.c:950
 __sock_release net/socket.c:649 [inline]
 sock_close+0xcd/0x230 net/socket.c:1336
 __fput+0x3bf/0x890 fs/file_table.c:280
 task_work_run+0x129/0x1a0 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:175
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x5d/0x250 kernel/entry/common.c:301
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fc5e5c030a8
Code: 48 8b 05 83 9d 0d 00 64 c7 00 16 00 00 00 83 c8 ff 48 83 c4 20 5b c3 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 5b 48 8b 15 51 9d 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffc386bcbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007fc5e5c030a8
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 000000000000000c
RBP: 00007ffc386dcf98 R08: 0000000000000007 R09: 4043a00b2877dbd7
R10: 0000000000004000 R11: 0000000000000246 R12: 0000562ca6f9ae60
R13: 00007ffc386ccdd8 R14: 0000000000000148 R15: 0000000000000004
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.059 msecs