====================================================== WARNING: possible circular locking dependency detected 5.16.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/14544 is trying to acquire lock: ffff88806cd489e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: skb_queue_tail+0x21/0x140 net/core/skbuff.c:3341 but task is already holding lock: ffff88806cd48e78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock net/unix/af_unix.c:1276 [inline] ffff88806cd48e78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock+0x77/0xa0 net/unix/af_unix.c:1268 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:87 [inline] sk_diag_fill+0xaaf/0x10d0 net/unix/diag.c:155 sk_diag_dump net/unix/diag.c:193 [inline] unix_diag_dump+0x3b9/0x620 net/unix/diag.c:221 netlink_dump+0x4b2/0xb70 net/netlink/af_netlink.c:2268 __netlink_dump_start+0x644/0x900 net/netlink/af_netlink.c:2373 netlink_dump_start include/linux/netlink.h:254 [inline] unix_diag_handler_dump+0x43b/0x840 net/unix/diag.c:320 __sock_diag_cmd net/core/sock_diag.c:235 [inline] sock_diag_rcv_msg+0x31a/0x440 net/core/sock_diag.c:266 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:277 netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343 netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 sock_write_iter+0x289/0x3c0 net/socket.c:1061 call_write_iter include/linux/fs.h:2086 [inline] do_iter_readv_writev+0x47a/0x750 fs/read_write.c:725 do_iter_write+0x188/0x710 fs/read_write.c:851 vfs_writev+0x1aa/0x630 fs/read_write.c:924 do_writev+0x27f/0x300 fs/read_write.c:967 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:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a2c/0x5470 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5639 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604 __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:3341 unix_dgram_sendmsg+0xeeb/0x1a10 net/unix/af_unix.c:2027 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 io_send+0x1bd/0x450 fs/io_uring.c:5000 io_issue_sqe+0x374f/0x72e0 fs/io_uring.c:6733 __io_queue_sqe fs/io_uring.c:7057 [inline] io_req_task_submit+0xce/0x530 fs/io_uring.c:2447 io_apoll_task_func+0x1e6/0x250 fs/io_uring.c:5589 handle_tw_list fs/io_uring.c:2334 [inline] tctx_task_work+0x19a/0xee0 fs/io_uring.c:2368 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_signal include/linux/tracehook.h:213 [inline] handle_signal_work kernel/entry/common.c:146 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x256/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 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.5/14544: #0: ffff888049f060a8 (&ctx->uring_lock){+.+.}-{3:3}, at: handle_tw_list fs/io_uring.c:2331 [inline] #0: ffff888049f060a8 (&ctx->uring_lock){+.+.}-{3:3}, at: tctx_task_work+0x29f/0xee0 fs/io_uring.c:2368 #1: ffff88806cd48e78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock net/unix/af_unix.c:1276 [inline] #1: ffff88806cd48e78 (&u->lock/1){+.+.}-{2:2}, at: unix_state_double_lock+0x77/0xa0 net/unix/af_unix.c:1268 stack backtrace: CPU: 1 PID: 14544 Comm: syz-executor.5 Not tainted 5.16.0-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:2143 check_prev_add kernel/locking/lockdep.c:3063 [inline] check_prevs_add kernel/locking/lockdep.c:3186 [inline] validate_chain kernel/locking/lockdep.c:3801 [inline] __lock_acquire+0x2a2c/0x5470 kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5639 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5604 __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:3341 unix_dgram_sendmsg+0xeeb/0x1a10 net/unix/af_unix.c:2027 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:725 io_send+0x1bd/0x450 fs/io_uring.c:5000 io_issue_sqe+0x374f/0x72e0 fs/io_uring.c:6733 __io_queue_sqe fs/io_uring.c:7057 [inline] io_req_task_submit+0xce/0x530 fs/io_uring.c:2447 io_apoll_task_func+0x1e6/0x250 fs/io_uring.c:5589 handle_tw_list fs/io_uring.c:2334 [inline] tctx_task_work+0x19a/0xee0 fs/io_uring.c:2368 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_signal include/linux/tracehook.h:213 [inline] handle_signal_work kernel/entry/common.c:146 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x256/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f7a5b01bfe9 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:00007f7a59991168 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000080 RBX: 00007f7a5b12ef60 RCX: 00007f7a5b01bfe9 RDX: 0000000000000000 RSI: 0000000000002a6e RDI: 0000000000000003 RBP: 00007f7a5b07608d R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7a5b662b1f R14: 00007f7a59991300 R15: 0000000000022000