Similarly to dad9b335c694 ("netdevice: Fix promiscuity and allmulti
overflow"), we should not decrease promiscuity if it is already 0.
An example is after adding a team interface to bridge, the team interface
will enter promisc mode. Then if we add a slave to team0, the slave will
keep promisc off. If we remove team from bridge, both team0 and slave will
decrease the promiscuity, which will cause a negative overflow on the slave.
The team's issue will be fixed in a separate patch.
Reviewed-by: Stefano Brivio <sbri...@redhat.com>
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
---
net/core/dev.c | 54 ++++++++++++++++++++++----------------------------
1 file changed, 24 insertions(+), 30 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 2b67f2aa59dd..9744e9f696ba 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7338,22 +7338,19 @@ static int __dev_set_promiscuity(struct net_device
*dev, int inc, bool notify)
ASSERT_RTNL();
- dev->flags |= IFF_PROMISC;
- dev->promiscuity += inc;
- if (dev->promiscuity == 0) {
- /*
- * Avoid overflow.
- * If inc causes overflow, untouch promisc and return error.
- */
- if (inc < 0)
- dev->flags &= ~IFF_PROMISC;
- else {
- dev->promiscuity -= inc;
- pr_warn("%s: promiscuity touches roof, set promiscuity
failed. promiscuity feature of device might be broken.\n",
- dev->name);
- return -EOVERFLOW;
- }
+ if ((inc < 0 && dev->promiscuity + inc > dev->promiscuity) ||
+ (inc > 0 && dev->promiscuity + inc < dev->promiscuity)) {
+ pr_warn("%s: increase promiscuity %u by %d failed, promiscuity
feature of device might be broken.\n",
+ dev->name, dev->promiscuity, inc);
+ return -EOVERFLOW;
}
+
+ dev->promiscuity += inc;
+ if (dev->promiscuity)
+ dev->flags |= IFF_PROMISC;
+ else
+ dev->flags &= ~IFF_PROMISC;
+
if (dev->flags != old_flags) {
pr_info("device %s %s promiscuous mode\n",
dev->name,
@@ -7409,22 +7406,19 @@ static int __dev_set_allmulti(struct net_device *dev,
int inc, bool notify)
ASSERT_RTNL();
- dev->flags |= IFF_ALLMULTI;
- dev->allmulti += inc;
- if (dev->allmulti == 0) {
- /*
- * Avoid overflow.
- * If inc causes overflow, untouch allmulti and return error.
- */
- if (inc < 0)
- dev->flags &= ~IFF_ALLMULTI;
- else {
- dev->allmulti -= inc;
- pr_warn("%s: allmulti touches roof, set allmulti
failed. allmulti feature of device might be broken.\n",
- dev->name);
- return -EOVERFLOW;
- }
+ if ((inc < 0 && dev->allmulti + inc > dev->allmulti) ||
+ (inc > 0 && dev->allmulti + inc < dev->allmulti)) {
+ pr_warn("%s: increase allmulti %u by %d failed, allmulti
feature of device might be broken.\n",
+ dev->name, dev->allmulti, inc);
+ return -EOVERFLOW;
}
+
+ dev->allmulti += inc;
+ if (dev->allmulti)
+ dev->flags |= IFF_ALLMULTI;
+ else
+ dev->flags &= ~IFF_ALLMULTI;
+
if (dev->flags ^ old_flags) {
dev_change_rx_flags(dev, IFF_ALLMULTI);
dev_set_rx_mode(dev);
--
2.19.2
