NACK/Cmnt: [SRU][B][PATCH 0/1] vrf: fix refcnt leak with vxlan slaves

Stefan Bader stefan.bader at
Tue Oct 5 08:16:08 UTC 2021

On 04.10.21 20:37, Luke Nowakowski-Krijger wrote:
> This is a backport request by Nicolas Dichtel <nicolas.dichtel at>
> BugLink:
> [Impact]
> There are cases, where deleting a VRF device can hang waiting for the refcnt
> to drop to 0, with the message:
>    unregister_netdevice: waiting for vrf1 to become free. Usage count = 1
> This is fixed upstream with commit b87b04f5019e
> ("ipv4: Fix device used for dst_alloc with local routes"), included in linux
> v5.13. The original patch, which has introduced the bug, is included in
> linux v4.10.
> [Backports]
> Removed updates to tools/testing/selftests/net/ as they do not
> exist for bionic. Also changed the struct referenced in the patch from
> fib_nh_common to fib_nh as well as the associated accesses to the
> struct.
> [Test Case]
> Reproduced the bug with the upstream test case which also is the test in
> the original patch added to
> Confirmed that after the patch was applied the test case does not hang
> and successfully removes VRF device.
> [Regression Potential]
> Relatively straightforward in that it links a new dst to a vrf device
> isntead of the loopback if there is a valid nexthop device.
> David Ahern (1):
>    ipv4: Fix device used for dst_alloc with local routes
>   net/ipv4/route.c | 15 ++++++++++++++-
>   1 file changed, 14 insertions(+), 1 deletion(-)

This is not about the patches themselves. Just the fact that they are sent as 
separate threads. This is one request with the same change, just for Bionic it 
needs some adjustments. Which is one things that is much simpler to compare when 
the versions are grouped together. Also it is simpler to check whether all 
series have been covered. And finally make it more likely to get applied around 
the same time.

To do this, you would prepare one patch with --cover-email and the other with 
--start-number which is +1 from the first set, Here it would be 2.
Then the subjects should be adjusted. I would propose

[SRU][B/F][PATCH 0/1] ....
+- [SRU][B][PATCH 1/1] ...
+- [SRU][F][PATCH 1/1] ...


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