====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc5-syzkaller-00053-ge33c4963bf53 #0 Not tainted ------------------------------------------------------ syz-executor.0/26663 is trying to acquire lock: ffffffff8f69aaf8 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffffffff8f69aaf8 (unix_gc_lock){+.+.}-{2:2}, at: unix_notinflight+0x204/0x390 net/unix/garbage.c:140 but task is already holding lock: ffff88807b488e70 (&u->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffff88807b488e70 (&u->lock){+.+.}-{2:2}, at: unix_stream_read_generic+0x449/0x2700 net/unix/af_unix.c:2738 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&u->lock){+.+.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __unix_gc+0x40e/0xf70 net/unix/garbage.c:302 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #0 (unix_gc_lock){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] unix_notinflight+0x204/0x390 net/unix/garbage.c:140 unix_detach_fds net/unix/af_unix.c:1819 [inline] unix_destruct_scm+0x221/0x350 net/unix/af_unix.c:1876 skb_release_head_state+0x100/0x250 net/core/skbuff.c:1188 skb_release_all net/core/skbuff.c:1200 [inline] __kfree_skb net/core/skbuff.c:1216 [inline] kfree_skb_reason+0x16d/0x3b0 net/core/skbuff.c:1252 kfree_skb include/linux/skbuff.h:1262 [inline] manage_oob net/unix/af_unix.c:2672 [inline] unix_stream_read_generic+0x1125/0x2700 net/unix/af_unix.c:2749 unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2950 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1068 ____sys_recvmsg+0x1db/0x470 net/socket.c:2803 ___sys_recvmsg net/socket.c:2845 [inline] __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2875 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&u->lock); lock(unix_gc_lock); lock(&u->lock); lock(unix_gc_lock); *** DEADLOCK *** 2 locks held by syz-executor.0/26663: #0: ffff88807b488d80 (&u->iolock){+.+.}-{3:3}, at: unix_stream_read_generic+0x18a4/0x2700 net/unix/af_unix.c:2787 #1: ffff88807b488e70 (&u->lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff88807b488e70 (&u->lock){+.+.}-{2:2}, at: unix_stream_read_generic+0x449/0x2700 net/unix/af_unix.c:2738 stack backtrace: CPU: 0 PID: 26663 Comm: syz-executor.0 Not tainted 6.9.0-rc5-syzkaller-00053-ge33c4963bf53 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] unix_notinflight+0x204/0x390 net/unix/garbage.c:140 unix_detach_fds net/unix/af_unix.c:1819 [inline] unix_destruct_scm+0x221/0x350 net/unix/af_unix.c:1876 skb_release_head_state+0x100/0x250 net/core/skbuff.c:1188 skb_release_all net/core/skbuff.c:1200 [inline] __kfree_skb net/core/skbuff.c:1216 [inline] kfree_skb_reason+0x16d/0x3b0 net/core/skbuff.c:1252 kfree_skb include/linux/skbuff.h:1262 [inline] manage_oob net/unix/af_unix.c:2672 [inline] unix_stream_read_generic+0x1125/0x2700 net/unix/af_unix.c:2749 unix_stream_recvmsg+0x22b/0x2c0 net/unix/af_unix.c:2950 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1068 ____sys_recvmsg+0x1db/0x470 net/socket.c:2803 ___sys_recvmsg net/socket.c:2845 [inline] __sys_recvmsg+0x2f0/0x3e0 net/socket.c:2875 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f231887dea9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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:00007f23196b40c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007f23189abf80 RCX: 00007f231887dea9 RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000004 RBP: 00007f23188ca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f23189abf80 R15: 00007ffcd56fe8e8