[PATCH v1 net] ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().

[PATCH v1 net] ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().

[Kuniyuki Iwashima]

fib_check_nh_v6_gw() expects that fib6_nh_init() cleans up everything
when it fails.

Commit 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
moved fib_nh_common_init() before alloc_percpu_gfp() within fib6_nh_init()
but forgot to add cleanup for fib6_nh->nh_common.nhc_pcpu_rth_output in
case it fails to allocate fib6_nh->rt6i_pcpu, resulting in memleak.

Let's call fib_nh_common_release() and clear nhc_pcpu_rth_output in the
error path.

Note that we can remove the fib6_nh_release() call in nh_create_ipv6()
later in net-next.git.

Fixes: 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/ipv6/route.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ef2d23a1e3d5..bc6bcf5d7133 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3644,7 +3644,8 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
 		in6_dev_put(idev);
 
 	if (err) {
-		lwtstate_put(fib6_nh->fib_nh_lws);
+		fib_nh_common_release(&fib6_nh->nh_common);
+		fib6_nh->nh_common.nhc_pcpu_rth_output = NULL;
 		fib6_nh->fib_nh_lws = NULL;
 		netdev_put(dev, dev_tracker);
 	}
-- 
2.48.1

Re: [PATCH v1 net] ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Tue, 11 Mar 2025 18:03:25 -0700 you wrote:
> fib_check_nh_v6_gw() expects that fib6_nh_init() cleans up everything
> when it fails.
> 
> Commit 7dd73168e273 ("ipv6: Always allocate pcpu memory in a fib6_nh")
> moved fib_nh_common_init() before alloc_percpu_gfp() within fib6_nh_init()
> but forgot to add cleanup for fib6_nh->nh_common.nhc_pcpu_rth_output in
> case it fails to allocate fib6_nh->rt6i_pcpu, resulting in memleak.
> 
> [...]

Here is the summary with links:
  - [v1,net] ipv6: Fix memleak of nhc_pcpu_rth_output in fib_check_nh_v6_gw().
    https://git.kernel.org/netdev/net/c/9740890ee20e

You are awesome, thank you!
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