====================================================== WARNING: possible circular locking dependency detected 5.15.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/18226 is trying to acquire lock: ffff8880283fd9e0 (rlock-AF_UNIX){+.+.}-{2:2}, at: skb_queue_tail+0x21/0x140 net/core/skbuff.c:3319 but task is already holding lock: ffff8880283fde78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock net/unix/af_unix.c:1196 [inline] ffff8880283fde78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock+0x77/0xa0 net/unix/af_unix.c:1188 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&u->lock/1){+.+.}-{2:2}: _raw_spin_lock_nested+0x30/0x40 kernel/locking/spinlock.c:368 sk_diag_dump_icons net/unix/diag.c:86 [inline] sk_diag_fill+0xaa7/0x1100 net/unix/diag.c:154 sk_diag_dump net/unix/diag.c:192 [inline] unix_diag_dump+0x399/0x590 net/unix/diag.c:220 netlink_dump+0x4b9/0xb70 net/netlink/af_netlink.c:2284 __netlink_dump_start+0x642/0x900 net/netlink/af_netlink.c:2389 netlink_dump_start include/linux/netlink.h:258 [inline] unix_diag_handler_dump+0x411/0x7d0 net/unix/diag.c:319 __sock_diag_cmd net/core/sock_diag.c:234 [inline] sock_diag_rcv_msg+0x31a/0x440 net/core/sock_diag.c:265 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2510 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1935 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 sock_no_sendpage+0xf6/0x140 net/core/sock.c:2998 kernel_sendpage.part.0+0x1a0/0x340 net/socket.c:3504 kernel_sendpage net/socket.c:3501 [inline] sock_sendpage+0xe5/0x140 net/socket.c:1003 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364 splice_from_pipe_feed fs/splice.c:418 [inline] __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562 splice_from_pipe fs/splice.c:597 [inline] generic_splice_sendpage+0xd4/0x140 fs/splice.c:746 do_splice_from fs/splice.c:767 [inline] do_splice+0xb7e/0x1960 fs/splice.c:1079 __do_splice+0x134/0x250 fs/splice.c:1144 __do_sys_splice fs/splice.c:1350 [inline] __se_sys_splice fs/splice.c:1332 [inline] __x64_sys_splice+0x198/0x250 fs/splice.c:1332 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (rlock-AF_UNIX){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 skb_queue_tail+0x21/0x140 net/core/skbuff.c:3319 unix_dgram_sendmsg+0xf60/0x1950 net/unix/af_unix.c:1939 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 io_send+0x349/0x4d0 fs/io_uring.c:4843 io_issue_sqe+0x3814/0x7010 fs/io_uring.c:6651 __io_queue_sqe fs/io_uring.c:6978 [inline] io_queue_sqe fs/io_uring.c:7020 [inline] io_submit_sqe fs/io_uring.c:7223 [inline] io_submit_sqes+0x1bca/0x8a20 fs/io_uring.c:7329 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10043 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae 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.4/18226: #0: ffff8880287b70a8 (&ctx->uring_lock){+.+.}-{3:3}, at: __do_sys_io_uring_enter+0xf60/0x1f50 fs/io_uring.c:10042 #1: ffff8880283fde78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock net/unix/af_unix.c:1196 [inline] #1: ffff8880283fde78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock+0x77/0xa0 net/unix/af_unix.c:1188 stack backtrace: CPU: 0 PID: 18226 Comm: syz-executor.4 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2131 check_prev_add kernel/locking/lockdep.c:3051 [inline] check_prevs_add kernel/locking/lockdep.c:3174 [inline] validate_chain kernel/locking/lockdep.c:3789 [inline] __lock_acquire+0x2a07/0x54a0 kernel/locking/lockdep.c:5015 lock_acquire kernel/locking/lockdep.c:5625 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5590 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162 skb_queue_tail+0x21/0x140 net/core/skbuff.c:3319 unix_dgram_sendmsg+0xf60/0x1950 net/unix/af_unix.c:1939 sock_sendmsg_nosec net/socket.c:704 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:724 io_send+0x349/0x4d0 fs/io_uring.c:4843 io_issue_sqe+0x3814/0x7010 fs/io_uring.c:6651 __io_queue_sqe fs/io_uring.c:6978 [inline] io_queue_sqe fs/io_uring.c:7020 [inline] io_submit_sqe fs/io_uring.c:7223 [inline] io_submit_sqes+0x1bca/0x8a20 fs/io_uring.c:7329 __do_sys_io_uring_enter+0xf6e/0x1f50 fs/io_uring.c:10043 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fdaa1406ae9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fda9e97c188 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fdaa1519f60 RCX: 00007fdaa1406ae9 RDX: 0000000000000000 RSI: 0000000000002a6e RDI: 0000000000000003 RBP: 00007fdaa1460f25 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffca769dbf R14: 00007fda9e97c300 R15: 0000000000022000