Dmitry got the following recursive locking report while running syzkaller
fuzzer, the 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
This warning is caused by the lock held by sctp_getsockopt() is on one
socket, while the other lock that sctp_close() is getting later is on
the newly created (which failed) socket during peeloff operation.
This patch is to avoid this warning by use lock_sock with subclass
SINGLE_DEPTH_NESTING as Wang Cong and Marcelo's suggestion.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Suggested-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
6dfe4b97e0