blob: bdef452dda039d97b87dfc012fad08eafc39b32c [file] [log] [blame]
From bde77e2e45d7358ed3a81e78465767544777cb68 Mon Sep 17 00:00:00 2001
From: Mahesh Bandewar <>
Date: Mon, 9 Mar 2020 15:57:07 -0700
Subject: [PATCH] macvlan: add cond_resched() during multicast processing
commit ce9a4186f9ac475c415ffd20348176a4ea366670 upstream.
The Rx bound multicast packets are deferred to a workqueue and
macvlan can also suffer from the same attack that was discovered
by Syzbot for IPvlan. This solution is not as effective as in
IPvlan. IPvlan defers all (Tx and Rx) multicast packet processing
to a workqueue while macvlan does this way only for the Rx. This
fix should address the Rx codition to certain extent.
Tx is still suseptible. Tx multicast processing happens when
.ndo_start_xmit is called, hence we cannot add cond_resched().
However, it's not that severe since the user which is generating
/ flooding will be affected the most.
Fixes: 412ca1550cbe ("macvlan: Move broadcasts into a work queue")
Signed-off-by: Mahesh Bandewar <>
Signed-off-by: David S. Miller <>
Signed-off-by: Paul Gortmaker <>
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 50f253160d7e..52cc38359960 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -334,6 +334,8 @@ static void macvlan_process_broadcast(struct work_struct *w)
if (src)
+ cond_resched();