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authorDaniel Borkmann <daniel@iogearbox.net>2018-10-16 22:31:35 +0300
committerDavid S. Miller <davem@davemloft.net>2018-10-16 22:38:41 +0300
commitaadd4355918fe6e9044a9042fa5968e0a0901681 (patch)
treebde5becd6794d32ac8fb2c951570b705266cc162 /net/ipv4/tcp_ulp.c
parent29ce85f349c2f77a3c035f70fafeaa8b22608328 (diff)
downloadlinux-aadd4355918fe6e9044a9042fa5968e0a0901681.tar.xz
tcp, ulp: remove socket lock assertion on ULP cleanup
Eric reported that syzkaller triggered a splat in tcp_cleanup_ulp() where assertion sock_owned_by_me() failed. This happened through inet_csk_prepare_forced_close() first releasing the socket lock, then calling into tcp_done(newsk) which is called after the inet_csk_prepare_forced_close() and therefore without the socket lock held. The sock_owned_by_me() assertion can generally be removed as the only place where tcp_cleanup_ulp() is called from now is out of inet_csk_destroy_sock() -> sk->sk_prot->destroy() where socket is in dead state and unreachable. Therefore, add a comment why the check is not needed instead. Fixes: 8b9088f806e1 ("tcp, ulp: enforce sock_owned_by_me upon ulp init and cleanup") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ulp.c')
-rw-r--r--net/ipv4/tcp_ulp.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index a9162aa11af9..95df7f7f6328 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -99,8 +99,10 @@ void tcp_cleanup_ulp(struct sock *sk)
{
struct inet_connection_sock *icsk = inet_csk(sk);
- sock_owned_by_me(sk);
-
+ /* No sock_owned_by_me() check here as at the time the
+ * stack calls this function, the socket is dead and
+ * about to be destroyed.
+ */
if (!icsk->icsk_ulp_ops)
return;