[PATCH 4.1 19/43] sctp: update the netstamp_needed counter when copying sockets

From: Greg Kroah-Hartman
Date: Wed Jan 20 2016 - 18:15:02 EST


4.1-stable review patch. If anyone has any objections, please let me know.

------------------

From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>

[ Upstream commit 01ce63c90170283a9855d1db4fe81934dddce648 ]

Dmitry Vyukov reported that SCTP was triggering a WARN on socket destroy
related to disabling sock timestamp.

When SCTP accepts an association or peel one off, it copies sock flags
but forgot to call net_enable_timestamp() if a packet timestamping flag
was copied, leading to extra calls to net_disable_timestamp() whenever
such clones were closed.

The fix is to call net_enable_timestamp() whenever we copy a sock with
that flag on, like tcp does.

Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Acked-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/sock.h | 2 ++
net/core/sock.c | 2 --
net/sctp/socket.c | 3 +++
3 files changed, 5 insertions(+), 2 deletions(-)

--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -722,6 +722,8 @@ enum sock_flags {
SOCK_SELECT_ERR_QUEUE, /* Wake select on error queue */
};

+#define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
+
static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
{
nsk->sk_flags = osk->sk_flags;
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -421,8 +421,6 @@ static void sock_warn_obsolete_bsdism(co
}
}

-#define SK_FLAGS_TIMESTAMP ((1UL << SOCK_TIMESTAMP) | (1UL << SOCK_TIMESTAMPING_RX_SOFTWARE))
-
static void sock_disable_timestamp(struct sock *sk, unsigned long flags)
{
if (sk->sk_flags & flags) {
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -7207,6 +7207,9 @@ void sctp_copy_sock(struct sock *newsk,
newinet->mc_ttl = 1;
newinet->mc_index = 0;
newinet->mc_list = NULL;
+
+ if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
+ net_enable_timestamp();
}

static inline void sctp_copy_descendant(struct sock *sk_to,