This is a note to let you know that I've just added the patch titled netdevsim: fix backwards compatibility in nsim_get_iflink() to the 6.9-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: netdevsim-fix-backwards-compatibility-in-nsim_get_if.patch and it can be found in the queue-6.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit acbabb076235e40aa7b36542eb70c41f05393c2e Author: David Wei <dw@xxxxxxxxxxx> Date: Thu Jun 6 07:59:08 2024 -0700 netdevsim: fix backwards compatibility in nsim_get_iflink() [ Upstream commit 5add2f7288468f35a374620dabf126c13baaea9c ] The default ndo_get_iflink() implementation returns the current ifindex of the netdev. But the overridden nsim_get_iflink() returns 0 if the current nsim is not linked, breaking backwards compatibility for userspace that depend on this behaviour. Fix the problem by returning the current ifindex if not linked to a peer. Fixes: 8debcf5832c3 ("netdevsim: add ndo_get_iflink() implementation") Reported-by: Yu Watanabe <watanabe.yu@xxxxxxxxx> Suggested-by: Yu Watanabe <watanabe.yu@xxxxxxxxx> Signed-off-by: David Wei <dw@xxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index 8330bc0bcb7e5..d405809030aab 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -292,7 +292,8 @@ static int nsim_get_iflink(const struct net_device *dev) rcu_read_lock(); peer = rcu_dereference(nsim->peer); - iflink = peer ? READ_ONCE(peer->netdev->ifindex) : 0; + iflink = peer ? READ_ONCE(peer->netdev->ifindex) : + READ_ONCE(dev->ifindex); rcu_read_unlock(); return iflink;