This is a note to let you know that I've just added the patch titled
netlink: not trim skb for mmaped socket when dump
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:
netlink-not-trim-skb-for-mmaped-socket-when-dump.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@xxxxxxxxxxxxxxx> know about it.
>From aa3a022094fac7f6e48050e139fa8a5a2e3265ce Mon Sep 17 00:00:00 2001
From: Ken-ichirou MATSUZAWA <chamaken@xxxxxxxxx>
Date: Fri, 29 Jan 2016 10:45:50 +0900
Subject: netlink: not trim skb for mmaped socket when dump
From: Ken-ichirou MATSUZAWA <chamaken@xxxxxxxxx>
commit aa3a022094fac7f6e48050e139fa8a5a2e3265ce upstream.
We should not trim skb for mmaped socket since its buf size is fixed
and userspace will read as frame which data equals head. mmaped
socket will not call recvmsg, means max_recvmsg_len is 0,
skb_reserve was not called before commit: db65a3aaf29e.
Fixes: db65a3aaf29e (netlink: Trim skb to alloc size to avoid MSG_TRUNC)
Signed-off-by: Ken-ichirou MATSUZAWA <chamas@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netlink/af_netlink.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2179,7 +2179,8 @@ static int netlink_dump(struct sock *sk)
* reasonable static buffer based on the expected largest dump of a
* single netdev. The outcome is MSG_TRUNC error.
*/
- skb_reserve(skb, skb_tailroom(skb) - alloc_size);
+ if (!netlink_rx_is_mmaped(sk))
+ skb_reserve(skb, skb_tailroom(skb) - alloc_size);
netlink_skb_set_owner_r(skb, sk);
if (nlk->dump_done_errno > 0)
Patches currently in stable-queue which might be from chamaken@xxxxxxxxx are
queue-4.4/netlink-not-trim-skb-for-mmaped-socket-when-dump.patch
