Re: [PATCH 5.15.y 6/6] ipv6: release nexthop on device removal

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: eb02688c5c45c3e7af7e71f036a7144f5639cbfe

WARNING: Author mismatch between patch and upstream commit:
Backport author: Harshit Mogalapalli<harshit.m.mogalapalli@oracle.com>
Commit author: Paolo Abeni<pabeni@redhat.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.13.y | Present (exact SHA1)
6.12.y | Present (different SHA1: 0e4c6faaef8a)
6.6.y | Present (different SHA1: 43e25adc8026)
6.1.y | Present (different SHA1: b2f26a27ea3f)

Note: The patch differs from the upstream commit:
---
1:  eb02688c5c45c ! 1:  47cc8122c9644 ipv6: release nexthop on device removal
    @@ Metadata
      ## Commit message ##
         ipv6: release nexthop on device removal
     
    +    [ Upstream commit eb02688c5c45c3e7af7e71f036a7144f5639cbfe ]
    +
         The CI is hitting some aperiodic hangup at device removal time in the
         pmtu.sh self-test:
     
    @@ Commit message
         Reviewed-by: David Ahern <dsahern@kernel.org>
         Link: https://patch.msgid.link/604c45c188c609b732286b47ac2a451a40f6cf6d.1730828007.git.pabeni@redhat.com
         Signed-off-by: Jakub Kicinski <kuba@kernel.org>
    +    (cherry picked from commit eb02688c5c45c3e7af7e71f036a7144f5639cbfe)
    +    [Harshit: Resolved conflict due to missing commit: e5f80fcf869a ("ipv6:
    +    give an IPv6 dev to blackhole_netdev") and commit: b4cb4a1391dc ("net:
    +    use unrcu_pointer() helper") in linux-5.15.y]
    +    Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
     
      ## net/ipv6/route.c ##
    -@@ net/ipv6/route.c: static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
    - {
    - 	struct rt6_info *rt = dst_rt6_info(dst);
    +@@ net/ipv6/route.c: static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
      	struct inet6_dev *idev = rt->rt6i_idev;
    + 	struct net_device *loopback_dev =
    + 		dev_net(dev)->loopback_dev;
     +	struct fib6_info *from;
      
    - 	if (idev && idev->dev != blackhole_netdev) {
    - 		struct inet6_dev *blackhole_idev = in6_dev_get(blackhole_netdev);
    -@@ net/ipv6/route.c: static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev)
    + 	if (idev && idev->dev != loopback_dev) {
    + 		struct inet6_dev *loopback_idev = in6_dev_get(loopback_dev);
    +@@ net/ipv6/route.c: static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
      			in6_dev_put(idev);
      		}
      	}
    -+	from = unrcu_pointer(xchg(&rt->from, NULL));
    ++	from = xchg((__force struct fib6_info **)&rt->from, NULL);
     +	fib6_info_release(from);
      }
      
    @@ net/ipv6/route.c: static void rt6_remove_exception(struct rt6_exception_bucket *
      	/* purge completely the exception to allow releasing the held resources:
      	 * some [sk] cache may keep the dst around for unlimited time
      	 */
    --	from = unrcu_pointer(xchg(&rt6_ex->rt6i->from, NULL));
    +-	from = xchg((__force struct fib6_info **)&rt6_ex->rt6i->from, NULL);
     -	fib6_info_release(from);
      	dst_dev_put(&rt6_ex->rt6i->dst);
      
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |