tcp: do not release socket ownership in tcp_close()

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commit 8873c064d1 upstream.

syzkaller was able to hit the WARN_ON(sock_owned_by_user(sk));
in tcp_close()

While a socket is being closed, it is very possible other
threads find it in rtnetlink dump.

tcp_get_info() will acquire the socket lock for a short amount
of time (slow = lock_sock_fast(sk)/unlock_sock_fast(sk, slow);),
enough to trigger the warning.

Fixes: 67db3e4bfb ("tcp: no longer hold ehash lock while calling tcp_get_info()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Eric Dumazet 2018-10-01 23:24:26 -07:00 • committed by Greg Kroah-Hartman

parent 5999609a93

commit cddcc9959a

3 changed files with 5 additions and 9 deletions

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1

include/net/sock.h

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2

net/core/sock.c

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11

net/ipv4/tcp.c

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