====================================================== WARNING: possible circular locking dependency detected 5.15.110-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/11996 is trying to acquire lock: ffff88802d07e1e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: skb_queue_tail+0x32/0x120 net/core/skbuff.c:3355 but task is already holding lock: ffff88802d07e680 (&u->lock/1){+.+.}-{2:2}, at: unix_dgram_sendmsg+0x1001/0x2090 net/unix/af_unix.c:1924 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&u->lock/1){+.+.}-{2:2}: lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622 _raw_spin_lock_nested+0x2d/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0x6e6/0xfe0 net/unix/diag.c:156 sk_diag_dump net/unix/diag.c:195 [inline] unix_diag_dump+0x3a5/0x5a0 net/unix/diag.c:223 netlink_dump+0x606/0xc40 net/netlink/af_netlink.c:2307 __netlink_dump_start+0x52f/0x6f0 net/netlink/af_netlink.c:2412 netlink_dump_start include/linux/netlink.h:258 [inline] unix_diag_handler_dump+0x1be/0x810 net/unix/diag.c:323 sock_diag_rcv_msg+0xd5/0x400 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2533 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1356 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1952 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x39b/0x530 net/socket.c:1060 call_write_iter include/linux/fs.h:2103 [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 -> #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+0x1646/0x58b0 kernel/locking/lockdep.c:3787 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 skb_queue_tail+0x32/0x120 net/core/skbuff.c:3355 unix_dgram_sendmsg+0x15c1/0x2090 net/unix/af_unix.c:1947 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x39b/0x530 net/socket.c:1060 call_write_iter include/linux/fs.h:2103 [inline] io_write+0x84f/0xea0 io_uring/io_uring.c:3771 io_issue_sqe+0x176a/0xa770 io_uring/io_uring.c:6883 __io_queue_sqe+0x34/0x360 io_uring/io_uring.c:7191 io_queue_sqe io_uring/io_uring.c:7242 [inline] io_submit_sqe io_uring/io_uring.c:7419 [inline] io_submit_sqes+0x30fb/0xa410 io_uring/io_uring.c:7525 __do_sys_io_uring_enter io_uring/io_uring.c:10254 [inline] __se_sys_io_uring_enter+0x28b/0x21c0 io_uring/io_uring.c:10196 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 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&u->lock/1); lock(rlock-AF_UNIX); lock(&u->lock/1); lock(rlock-AF_UNIX); *** DEADLOCK *** 2 locks held by syz-executor.5/11996: #0: ffff8880776b00a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter io_uring/io_uring.c:10253 [inline] #0: ffff8880776b00a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __se_sys_io_uring_enter+0x280/0x21c0 io_uring/io_uring.c:10196 #1: ffff88802d07e680 (&u->lock/1){+.+.}-{2:2}, at: unix_dgram_sendmsg+0x1001/0x2090 net/unix/af_unix.c:1924 stack backtrace: CPU: 0 PID: 11996 Comm: syz-executor.5 Not tainted 5.15.110-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb 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+0x1646/0x58b0 kernel/locking/lockdep.c:3787 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5011 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5622 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd1/0x120 kernel/locking/spinlock.c:162 skb_queue_tail+0x32/0x120 net/core/skbuff.c:3355 unix_dgram_sendmsg+0x15c1/0x2090 net/unix/af_unix.c:1947 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg net/socket.c:724 [inline] sock_write_iter+0x39b/0x530 net/socket.c:1060 call_write_iter include/linux/fs.h:2103 [inline] io_write+0x84f/0xea0 io_uring/io_uring.c:3771 io_issue_sqe+0x176a/0xa770 io_uring/io_uring.c:6883 __io_queue_sqe+0x34/0x360 io_uring/io_uring.c:7191 io_queue_sqe io_uring/io_uring.c:7242 [inline] io_submit_sqe io_uring/io_uring.c:7419 [inline] io_submit_sqes+0x30fb/0xa410 io_uring/io_uring.c:7525 __do_sys_io_uring_enter io_uring/io_uring.c:10254 [inline] __se_sys_io_uring_enter+0x28b/0x21c0 io_uring/io_uring.c:10196 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: 0033:0x7fdee1d3a169 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdee028b168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fdee1e5a050 RCX: 00007fdee1d3a169 RDX: 0000000000000000 RSI: 00000000000001c9 RDI: 0000000000000003 RBP: 00007fdee1d95ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffca10533df R14: 00007fdee028b300 R15: 0000000000022000