From 6289a98f0817a4a457750d6345e754838eae9439 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Mon, 29 Mar 2021 12:25:22 -0700
Subject: [PATCH] sit: proper dev_{hold|put} in ndo_[un]init methods
Git-commit: 6289a98f0817a4a457750d6345e754838eae9439
Patch-mainline: v5.13-rc1
References: git-fixes
After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger
a warning [1]
Issue here is that:
- all dev_put() should be paired with a corresponding prior dev_hold().
- A driver doing a dev_put() in its ndo_uninit() MUST also
do a dev_hold() in its ndo_init(), only when ndo_init()
is returning 0.
Otherwise, register_netdevice() would call ndo_uninit()
in its error path and release a refcount too soon.
Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Wiesner <jwiesner@suse.de>
---
net/ipv6/sit.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index a241a7423b2a..7d92e240ccb7 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -209,8 +209,6 @@ static int ipip6_tunnel_create(struct net_device *dev)
ipip6_tunnel_clone_6rd(dev, sitn);
- dev_hold(dev);
-
ipip6_tunnel_link(sitn, t);
return 0;
@@ -1398,7 +1396,7 @@ static int ipip6_tunnel_init(struct net_device *dev)
dev->tstats = NULL;
return err;
}
-
+ dev_hold(dev);
return 0;
}
--
2.35.3