Hello, I've got the following recursive locking report while running syzkaller fuzzer on net-next/9c28286b1b4b9bce6e35dd4c8a1265f03802a89a: [ INFO: possible recursive locking detected ] 4.10.0+ #14 Not tainted --------------------------------------------- syz-executor3/5560 is trying to acquire lock: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff8401ebcd>] lock_sock include/net/sock.h:1460 [inline] (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff8401ebcd>] sctp_close+0xcd/0x9d0 net/sctp/socket.c:1497 but task is already holding lock: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff84038110>] lock_sock include/net/sock.h:1460 [inline] (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff84038110>] sctp_getsockopt+0x450/0x67e0 net/sctp/socket.c:6611 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(sk_lock-AF_INET6); lock(sk_lock-AF_INET6); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by syz-executor3/5560: #0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff84038110>] lock_sock include/net/sock.h:1460 [inline] #0: (sk_lock-AF_INET6){+.+.+.}, at: [<ffffffff84038110>] sctp_getsockopt+0x450/0x67e0 net/sctp/socket.c:6611 stack backtrace: CPU: 0 PID: 5560 Comm: syz-executor3 Not tainted 4.10.0+ #14 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:52 print_deadlock_bug kernel/locking/lockdep.c:1729 [inline] check_deadlock kernel/locking/lockdep.c:1773 [inline] validate_chain kernel/locking/lockdep.c:2251 [inline] __lock_acquire+0xef2/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 lock_sock_nested+0xcb/0x120 net/core/sock.c:2536 lock_sock include/net/sock.h:1460 [inline] sctp_close+0xcd/0x9d0 net/sctp/socket.c:1497 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432 sock_release+0x8d/0x1e0 net/socket.c:597 __sock_create+0x38b/0x870 net/socket.c:1226 sock_create+0x7f/0xa0 net/socket.c:1237 sctp_do_peeloff+0x1a2/0x440 net/sctp/socket.c:4879 sctp_getsockopt_peeloff net/sctp/socket.c:4914 [inline] sctp_getsockopt+0x111a/0x67e0 net/sctp/socket.c:6628 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2690 SYSC_getsockopt net/socket.c:1817 [inline] SyS_getsockopt+0x240/0x380 net/socket.c:1799 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x44fb79 RSP: 002b:00007f35f232bb58 EFLAGS: 00000212 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 0000000000000084 RCX: 000000000044fb79 RDX: 0000000000000066 RSI: 0000000000000084 RDI: 0000000000000006 RBP: 0000000000000006 R08: 0000000020119000 R09: 0000000000000000 R10: 000000002058dff8 R11: 0000000000000212 R12: 0000000000708000 R13: 0000000000000103 R14: 0000000000000001 R15: 0000000000000000 -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html