Patch "batman-adv: Avoid WARN_ON timing related checks" 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

    batman-adv: Avoid WARN_ON timing related checks

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:
     batman-adv-avoid-warn_on-timing-related-checks.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 Tue Nov 23 01:39:02 PM CET 2021
From: Sven Eckelmann <sven@narfation.org>
Date: Sat, 20 Nov 2021 13:39:39 +0100
Subject: batman-adv: Avoid WARN_ON timing related checks
To: stable@vger.kernel.org
Cc: b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann <sven@narfation.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, syzbot+c0b807de416427ff3dd1@syzkaller.appspotmail.com, Simon Wunderlich <sw@simonwunderlich.de>
Message-ID: <20211120123939.260723-12-sven@narfation.org>

From: Sven Eckelmann <sven@narfation.org>

commit 9f460ae31c4435fd022c443a6029352217a16ac1 upstream.

The soft/batadv interface for a queued OGM can be changed during the time
the OGM was queued for transmission and when the OGM is actually
transmitted by the worker.

But WARN_ON must be used to denote kernel bugs and not to print simple
warnings. A warning can simply be printed using pr_warn.

Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Reported-by: syzbot+c0b807de416427ff3dd1@syzkaller.appspotmail.com
Fixes: ef0a937f7a14 ("batman-adv: consider outgoing interface in OGM sending")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
[ bp: 4.4 backported: adjust context. ]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/batman-adv/bat_iv_ogm.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -526,8 +526,10 @@ static void batadv_iv_ogm_emit(struct ba
 	if (WARN_ON(!forw_packet->if_outgoing))
 		goto out;
 
-	if (WARN_ON(forw_packet->if_outgoing->soft_iface != soft_iface))
+	if (forw_packet->if_outgoing->soft_iface != soft_iface) {
+		pr_warn("%s: soft interface switch for queued OGM\n", __func__);
 		goto out;
+	}
 
 	if (forw_packet->if_incoming->if_status != BATADV_IF_ACTIVE)
 		goto out;


Patches currently in stable-queue which might be from sven@narfation.org are

queue-4.4/batman-adv-consider-fragmentation-for-needed_headroom.patch
queue-4.4/ath9k-fix-potential-interrupt-storm-on-queue-reset.patch
queue-4.4/batman-adv-set-.owner-to-this_module.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-from-bla-backbone-to-mesh.patch
queue-4.4/batman-adv-fix-multicast-tt-issues-with-bogus-roam-flags.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-in-bla-backbone-from-lan.patch
queue-4.4/batman-adv-reserve-needed_-room-for-fragments.patch
queue-4.4/net-batman-adv-fix-error-handling.patch
queue-4.4/batman-adv-keep-fragments-equally-sized.patch
queue-4.4/batman-adv-avoid-warn_on-timing-related-checks.patch
queue-4.4/batman-adv-prevent-duplicated-softif_vlan-entry.patch
queue-4.4/batman-adv-don-t-always-reallocate-the-fragmentation-skb-head.patch
queue-4.4/batman-adv-mcast-fix-duplicate-mcast-packets-in-bla-backbone-from-mesh.patch