====================================================== WARNING: possible circular locking dependency detected 6.2.0-rc2-syzkaller-00313-g9b43a525db12 #0 Not tainted ------------------------------------------------------ syz-executor.2/3995 is trying to acquire lock: ffff8880536d0680 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:87 [inline] ffff8880536d0680 (&u->lock/1){+.+.}-{2:2}, at: sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 but task is already holding lock: ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x909/0xfc0 net/unix/diag.c:157 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (rlock-AF_UNIX){+.+.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 skb_queue_tail+0x25/0x150 net/core/skbuff.c:3572 unix_dgram_sendmsg+0xf45/0x1bc0 net/unix/af_unix.c:2081 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 ____sys_sendmsg+0x334/0x8c0 net/socket.c:2476 ___sys_sendmsg+0x110/0x1b0 net/socket.c:2530 __sys_sendmmsg+0x18f/0x460 net/socket.c:2616 __do_sys_sendmmsg net/socket.c:2645 [inline] __se_sys_sendmmsg net/socket.c:2642 [inline] __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2642 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (&u->lock/1){+.+.}-{2:2}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 sk_diag_dump_icons net/unix/diag.c:87 [inline] sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 sk_diag_dump net/unix/diag.c:196 [inline] unix_diag_dump+0x456/0x730 net/unix/diag.c:220 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2286 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2391 netlink_dump_start include/linux/netlink.h:294 [inline] unix_diag_handler_dump net/unix/diag.c:319 [inline] unix_diag_handler_dump+0x654/0x9a0 net/unix/diag.c:308 __sock_diag_cmd net/core/sock_diag.c:238 [inline] sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 sock_write_iter+0x295/0x3d0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_writev+0x1aa/0x630 fs/read_write.c:934 do_writev+0x279/0x2f0 fs/read_write.c:977 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(rlock-AF_UNIX); lock(&u->lock/1); lock(rlock-AF_UNIX); lock(&u->lock/1); *** DEADLOCK *** 5 locks held by syz-executor.2/3995: #0: ffffffff8e0bfe08 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x1b/0x40 net/core/sock_diag.c:279 #1: ffffffff8e0bff88 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:233 [inline] #1: ffffffff8e0bff88 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x19f/0x440 net/core/sock_diag.c:269 #2: ffff888025790688 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: netlink_dump+0xbe/0xc50 net/netlink/af_netlink.c:2234 #3: ffff88807122b558 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #3: ffff88807122b558 (&net->unx.table.locks[i]){+.+.}-{2:2}, at: unix_diag_dump+0x1c3/0x730 net/unix/diag.c:214 #4: ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:350 [inline] #4: ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_dump_icons net/unix/diag.c:69 [inline] #4: ffff888028d931e8 (rlock-AF_UNIX){+.+.}-{2:2}, at: sk_diag_fill+0x909/0xfc0 net/unix/diag.c:157 stack backtrace: CPU: 0 PID: 3995 Comm: syz-executor.2 Not tainted 6.2.0-rc2-syzkaller-00313-g9b43a525db12 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2177 check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 _raw_spin_lock_nested+0x34/0x40 kernel/locking/spinlock.c:378 sk_diag_dump_icons net/unix/diag.c:87 [inline] sk_diag_fill+0x9f5/0xfc0 net/unix/diag.c:157 sk_diag_dump net/unix/diag.c:196 [inline] unix_diag_dump+0x456/0x730 net/unix/diag.c:220 netlink_dump+0x570/0xc50 net/netlink/af_netlink.c:2286 __netlink_dump_start+0x64b/0x910 net/netlink/af_netlink.c:2391 netlink_dump_start include/linux/netlink.h:294 [inline] unix_diag_handler_dump net/unix/diag.c:319 [inline] unix_diag_handler_dump+0x654/0x9a0 net/unix/diag.c:308 __sock_diag_cmd net/core/sock_diag.c:238 [inline] sock_diag_rcv_msg+0x31e/0x440 net/core/sock_diag.c:269 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2564 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:280 netlink_unicast_kernel net/netlink/af_netlink.c:1330 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1356 netlink_sendmsg+0x91b/0xe10 net/netlink/af_netlink.c:1932 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg+0xd3/0x120 net/socket.c:734 sock_write_iter+0x295/0x3d0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] do_iter_readv_writev+0x20b/0x3b0 fs/read_write.c:735 do_iter_write+0x182/0x700 fs/read_write.c:861 vfs_writev+0x1aa/0x630 fs/read_write.c:934 do_writev+0x279/0x2f0 fs/read_write.c:977 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd56e88c0c9 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:00007fd56f591168 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007fd56e9abf80 RCX: 00007fd56e88c0c9 RDX: 0000000000000001 RSI: 00000000200000c0 RDI: 0000000000000006 RBP: 00007fd56e8e7ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffca2369cf R14: 00007fd56f591300 R15: 0000000000022000