Patch "net: properly release sk_frag.page" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    net: properly release sk_frag.page

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-properly-release-sk_frag.page.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Mon Mar 27 18:22:09 CEST 2017
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 15 Mar 2017 13:21:28 -0700
Subject: net: properly release sk_frag.page

From: Eric Dumazet <edumazet@google.com>


[ Upstream commit 22a0e18eac7a9e986fec76c60fa4a2926d1291e2 ]

I mistakenly added the code to release sk->sk_frag in
sk_common_release() instead of sk_destruct()

TCP sockets using sk->sk_allocation == GFP_ATOMIC do no call
sk_common_release() at close time, thus leaking one (order-3) page.

iSCSI is using such sockets.

Fixes: 5640f7685831 ("net: use a per task frag allocator")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/core/sock.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1459,6 +1459,11 @@ void sk_destruct(struct sock *sk)
 		pr_debug("%s: optmem leakage (%d bytes) detected\n",
 			 __func__, atomic_read(&sk->sk_omem_alloc));
 
+	if (sk->sk_frag.page) {
+		put_page(sk->sk_frag.page);
+		sk->sk_frag.page = NULL;
+	}
+
 	if (sk->sk_peer_cred)
 		put_cred(sk->sk_peer_cred);
 	put_pid(sk->sk_peer_pid);
@@ -2691,11 +2696,6 @@ void sk_common_release(struct sock *sk)
 
 	sk_refcnt_debug_release(sk);
 
-	if (sk->sk_frag.page) {
-		put_page(sk->sk_frag.page);
-		sk->sk_frag.page = NULL;
-	}
-
 	sock_put(sk);
 }
 EXPORT_SYMBOL(sk_common_release);


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.4/ipv4-provide-stronger-user-input-validation-in-nl_fib_input.patch
queue-4.4/tcp-initialize-icsk_ack.lrcvtime-at-session-start-time.patch
queue-4.4/net-properly-release-sk_frag.page.patch