============================================
WARNING: possible recursive locking detected
6.1.84-syzkaller #0 Not tainted
--------------------------------------------
dhcpcd/3216 is trying to acquire lock:
ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: unix_notinflight+0x297/0x390 net/unix/scm.c:72
but task is already holding lock:
ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x1380 net/unix/garbage.c:214
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(unix_gc_lock);
lock(unix_gc_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
2 locks held by dhcpcd/3216:
#0: ffff888073a56210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#0: ffff888073a56210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: __sock_release net/socket.c:653 [inline]
#0: ffff888073a56210 (&sb->s_type->i_mutex_key#10){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1400
#1: ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#1: ffffffff8e396738 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x1380 net/unix/garbage.c:214
stack backtrace:
CPU: 0 PID: 3216 Comm: dhcpcd Not tainted 6.1.84-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2983 [inline]
check_deadlock kernel/locking/lockdep.c:3026 [inline]
validate_chain+0x4711/0x5950 kernel/locking/lockdep.c:3812
__lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
unix_notinflight+0x297/0x390 net/unix/scm.c:72
unix_detach_fds net/unix/scm.c:134 [inline]
unix_destruct_scm+0x21d/0x350 net/unix/scm.c:145
skb_release_head_state+0xf9/0x230 net/core/skbuff.c:843
skb_release_all net/core/skbuff.c:854 [inline]
__kfree_skb net/core/skbuff.c:870 [inline]
kfree_skb_reason+0x13d/0x390 net/core/skbuff.c:893
kfree_skb include/linux/skbuff.h:1225 [inline]
unix_gc+0xb2e/0x1380 net/unix/garbage.c:292
unix_release_sock+0xab8/0xcf0 net/unix/af_unix.c:669
unix_release+0x88/0xc0 net/unix/af_unix.c:1039
__sock_release net/socket.c:654 [inline]
sock_close+0xcd/0x230 net/socket.c:1400
__fput+0x3b7/0x890 fs/file_table.c:320
task_work_run+0x246/0x300 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f480d0dd0a8
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:00007ffe4d7a18b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007f480d0dd0a8
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000010
RBP: 00007ffe4d7c1c68 R08: 0000000000000007 R09: 96d59ce5aedcbe24
R10: 0000000000004000 R11: 0000000000000246 R12: 0000558f584c1ad0
R13: 00007ffe4d7b1aa8 R14: 0000000000000148 R15: 0000000000000004
</TASK>