This is a note to let you know that I've just added the patch titled
sit: proper dev_{hold|put} in ndo_[un]init methods
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sit-proper-dev_-hold-put-in-ndo_init-methods.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6289a98f0817a4a457750d6345e754838eae9439 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Mon, 29 Mar 2021 12:25:22 -0700
Subject: sit: proper dev_{hold|put} in ndo_[un]init methods
From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 6289a98f0817a4a457750d6345e754838eae9439 upstream.
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@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/sit.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -218,8 +218,6 @@ static int ipip6_tunnel_create(struct ne
ipip6_tunnel_clone_6rd(dev, sitn);
- dev_hold(dev);
-
ipip6_tunnel_link(sitn, t);
return 0;
@@ -1456,7 +1454,7 @@ static int ipip6_tunnel_init(struct net_
dev->tstats = NULL;
return err;
}
-
+ dev_hold(dev);
return 0;
}
Patches currently in stable-queue which might be from edumazet@xxxxxxxxxx are
queue-5.12/ip6_tunnel-sit-proper-dev_-hold-put-in-ndo_init-methods.patch
queue-5.12/sit-proper-dev_-hold-put-in-ndo_init-methods.patch
queue-5.12/ip6_gre-proper-dev_-hold-put-in-ndo_init-methods.patch
queue-5.12/ipv6-remove-extra-dev_hold-for-fallback-tunnels.patch
