====================================================== WARNING: possible circular locking dependency detected 5.15.178-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor274/20648 is trying to acquire lock: ffff88807c96c9e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffff88807c96c9e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: scan_inflight+0x4a/0x480 net/unix/garbage.c:97 but task is already holding lock: ffffffff8dd3ba58 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] ffffffff8dd3ba58 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x13d0 net/unix/garbage.c:215 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (unix_gc_lock){+.+.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] unix_notinflight+0x138/0x380 net/unix/scm.c:73 unix_detach_fds net/unix/scm.c:136 [inline] unix_destruct_scm+0x21d/0x350 net/unix/scm.c:147 skb_release_head_state+0xf9/0x230 net/core/skbuff.c:729 skb_release_all net/core/skbuff.c:740 [inline] __kfree_skb net/core/skbuff.c:756 [inline] consume_skb+0x72/0x140 net/core/skbuff.c:914 queue_oob+0x6cf/0xad0 net/unix/af_unix.c:2000 unix_stream_sendmsg+0xe0a/0x1070 net/unix/af_unix.c:2105 sock_sendmsg_nosec net/socket.c:704 [inline] __sock_sendmsg net/socket.c:716 [inline] ____sys_sendmsg+0x59e/0x8f0 net/socket.c:2436 ___sys_sendmsg+0x252/0x2e0 net/socket.c:2490 __sys_sendmsg net/socket.c:2519 [inline] __do_sys_sendmsg net/socket.c:2528 [inline] __se_sys_sendmsg+0x19a/0x260 net/socket.c:2526 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 -> #0 (rlock-AF_UNIX){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] scan_inflight+0x4a/0x480 net/unix/garbage.c:97 scan_children+0x2b0/0x460 net/unix/garbage.c:137 unix_gc+0x4bf/0x13d0 net/unix/garbage.c:273 unix_release_sock+0x91c/0xaa0 net/unix/af_unix.c:598 unix_release+0x88/0xc0 net/unix/af_unix.c:933 __sock_release net/socket.c:649 [inline] sock_close+0xcd/0x230 net/socket.c:1336 __fput+0x3fe/0x8e0 fs/file_table.c:280 task_work_run+0x129/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x6a3/0x2480 kernel/exit.c:874 do_group_exit+0x144/0x310 kernel/exit.c:996 get_signal+0xc66/0x14e0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(unix_gc_lock); lock(rlock-AF_UNIX); lock(unix_gc_lock); lock(rlock-AF_UNIX); *** DEADLOCK *** 2 locks held by syz-executor274/20648: #0: ffff888071166810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:789 [inline] #0: ffff888071166810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: __sock_release net/socket.c:648 [inline] #0: ffff888071166810 (&sb->s_type->i_mutex_key#11){+.+.}-{3:3}, at: sock_close+0x98/0x230 net/socket.c:1336 #1: ffffffff8dd3ba58 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline] #1: ffffffff8dd3ba58 (unix_gc_lock){+.+.}-{2:2}, at: unix_gc+0x115/0x13d0 net/unix/garbage.c:215 stack backtrace: CPU: 0 PID: 20648 Comm: syz-executor274 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 check_noncircular+0x2f8/0x3b0 kernel/locking/lockdep.c:2133 check_prev_add kernel/locking/lockdep.c:3053 [inline] check_prevs_add kernel/locking/lockdep.c:3172 [inline] validate_chain+0x1649/0x5930 kernel/locking/lockdep.c:3788 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:363 [inline] scan_inflight+0x4a/0x480 net/unix/garbage.c:97 scan_children+0x2b0/0x460 net/unix/garbage.c:137 unix_gc+0x4bf/0x13d0 net/unix/garbage.c:273 unix_release_sock+0x91c/0xaa0 net/unix/af_unix.c:598 unix_release+0x88/0xc0 net/unix/af_unix.c:933 __sock_release net/socket.c:649 [inline] sock_close+0xcd/0x230 net/socket.c:1336 __fput+0x3fe/0x8e0 fs/file_table.c:280 task_work_run+0x129/0x1a0 kernel/task_work.c:188 exit_task_work include/linux/task_work.h:33 [inline] do_exit+0x6a3/0x2480 kernel/exit.c:874 do_group_exit+0x144/0x310 kernel/exit.c:996 get_signal+0xc66/0x14e0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x97/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fb32a4de859 Code: Unable to access opcode bytes at RIP 0x7fb32a4de82f. RSP: 002b:00007fb32a49f218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fb32a568348 RCX: 00007fb32a4de859 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fb32a568348 RBP: 00007fb32a568340 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb32a535074 R13: 0000400000000500 R14: 0000400000000610 R15: 0000400000000600