[PATCH net v3 2/3] ieee802154: Avoid calling WARN_ON() on -ENOMEM in cfg802154_switch_netns()

[Ivan Abramov]

It's pointless to call WARN_ON() in case of an allocation failure in
dev_change_net_namespace() and device_rename(), since it only leads to
useless splats caused by deliberate fault injections, so avoid it.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 66e5c2672cd1 ("ieee802154: add netns support")
Reported-by: syzbot+e0bd4e4815a910c0d...@syzkaller.appspotmail.com
Closes: 
https://lore.kernel.org/netdev/000000000000f4a1b7061f942...@google.com/#t
Reviewed-by: Kuniyuki Iwashima <kun...@amazon.com>
Reviewed-by: Miquel Raynal <miquel.ray...@bootlin.com>
Signed-off-by: Ivan Abramov <i.abra...@mt-integration.ru>
---
v3: Add Reviewed-by tags.
v2: Add Reported-by and Closes tags as per Kuniyuki Iwashima's observation.
Make sure to commit against latest netdev/net.

 net/ieee802154/core.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/ieee802154/core.c b/net/ieee802154/core.c
index 84d514430e45..987c633e2c54 100644
--- a/net/ieee802154/core.c
+++ b/net/ieee802154/core.c
@@ -228,8 +228,10 @@ int cfg802154_switch_netns(struct 
cfg802154_registered_device *rdev,
                        continue;
                wpan_dev->netdev->netns_immutable = false;
                err = dev_change_net_namespace(wpan_dev->netdev, net, "wpan%d");
-               if (err)
+               if (err) {
+                       WARN_ON(err && err != -ENOMEM);
                        break;
+               }
                wpan_dev->netdev->netns_immutable = true;
        }
 
@@ -237,7 +239,7 @@ int cfg802154_switch_netns(struct 
cfg802154_registered_device *rdev,
                goto errout;
 
        err = device_rename(&rdev->wpan_phy.dev, dev_name(&rdev->wpan_phy.dev));
-       WARN_ON(err);
+       WARN_ON(err && err != -ENOMEM);
 
        if (err)
                goto errout;
@@ -258,7 +260,7 @@ int cfg802154_switch_netns(struct 
cfg802154_registered_device *rdev,
                wpan_dev->netdev->netns_immutable = false;
                err = dev_change_net_namespace(wpan_dev->netdev, net,
                                               "wpan%d");
-               WARN_ON(err);
+               WARN_ON(err && err != -ENOMEM);
                wpan_dev->netdev->netns_immutable = true;
        }
 
-- 
2.39.5