summaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorSven Eckelmann <sven@narfation.org>2023-08-21 22:48:48 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-08-30 17:23:16 +0300
commit72e4a5a28ebfa55beafa57edd2f93123b6cec6aa (patch)
tree5a9775bc81c281962b04b537af228e16f01b87c7 /net
parentee1d443eefb2d0ed887b854681122dd43d3e09ef (diff)
downloadlinux-72e4a5a28ebfa55beafa57edd2f93123b6cec6aa.tar.xz
batman-adv: Hold rtnl lock during MTU update via netlink
commit 987aae75fc1041072941ffb622b45ce2359a99b9 upstream. The automatic recalculation of the maximum allowed MTU is usually triggered by code sections which are already rtnl lock protected by callers outside of batman-adv. But when the fragmentation setting is changed via batman-adv's own batadv genl family, then the rtnl lock is not yet taken. But dev_set_mtu requires that the caller holds the rtnl lock because it uses netdevice notifiers. And this code will then fail the check for this lock: RTNL: assertion failed at net/core/dev.c (1953) Cc: stable@vger.kernel.org Reported-by: syzbot+f8812454d9b3ac00d282@syzkaller.appspotmail.com Fixes: c6a953cce8d0 ("batman-adv: Trigger events for auto adjusted MTU") Signed-off-by: Sven Eckelmann <sven@narfation.org> Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/r/20230821-batadv-missing-mtu-rtnl-lock-v1-1-1c5a7bfe861e@narfation.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/batman-adv/netlink.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c
index 121459704b06..931bc3b5c6df 100644
--- a/net/batman-adv/netlink.c
+++ b/net/batman-adv/netlink.c
@@ -496,7 +496,10 @@ static int batadv_netlink_set_mesh(struct sk_buff *skb, struct genl_info *info)
attr = info->attrs[BATADV_ATTR_FRAGMENTATION_ENABLED];
atomic_set(&bat_priv->fragmentation, !!nla_get_u8(attr));
+
+ rtnl_lock();
batadv_update_min_mtu(bat_priv->soft_iface);
+ rtnl_unlock();
}
if (info->attrs[BATADV_ATTR_GW_BANDWIDTH_DOWN]) {