[PATCH mptcp-net] mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

[PATCH mptcp-net] mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

[Matthieu Baerts (NGI0)]

When an ADD_ADDR entry is reused, the timer is re-armed, because the
goal is to re-announce an ADD_ADDR, and eventually retransmit it if
needed.

In this case, the retransmission counter should be reset as well, so the
re-announced address gets its retransmissions back instead of relying on
what was left before, and possibly not being able to retransmit it.

Fixes: 304ab97f4c7c ("mptcp: allow ADD_ADDR reissuance by userspace PMs")
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260803-net-mptcp-misc-fixes-7-2-rc6-v2-0-b8f496d71664%40kernel.org?part=4
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 5e499ec1c50a..e46abbda7d27 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -462,10 +462,10 @@ bool mptcp_pm_announced_alloc(struct mptcp_sock *msk,
 
 	add_entry->addr = *addr;
 	add_entry->sock = msk;
-	add_entry->retrans_times = 0;
 
 	timer_setup(&add_entry->timer, mptcp_pm_add_addr_timer, 0);
 reset_timer:
+	add_entry->retrans_times = 0;
 	add_entry->timer_done = false;
 	timeout = mptcp_adjust_add_addr_timeout(msk);
 	if (timeout)

---
base-commit: 0715f5ba093a581def25b88da61c987b1719bc6d
change-id: 20260805-mptcp-pm-reset-retrans_time-8894830b0bd7

Best regards,
--  
Matthieu Baerts (NGI0) <matttbe@kernel.org>

Re: [PATCH mptcp-net] mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

[MPTCP CI]

Hi Matthieu,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Success! ✅
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Success! ✅
- KVM Validation: debug (only selftest_mptcp_join): Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/31015286192

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/c0750c235b43
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1140834


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)

Re: [PATCH mptcp-net] mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

[Mat Martineau]

On Wed, 5 Aug 2026, Matthieu Baerts (NGI0) wrote:

> When an ADD_ADDR entry is reused, the timer is re-armed, because the
> goal is to re-announce an ADD_ADDR, and eventually retransmit it if
> needed.
>
> In this case, the retransmission counter should be reset as well, so the
> re-announced address gets its retransmissions back instead of relying on
> what was left before, and possibly not being able to retransmit it.
>
> Fixes: 304ab97f4c7c ("mptcp: allow ADD_ADDR reissuance by userspace PMs")
> Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260803-net-mptcp-misc-fixes-7-2-rc6-v2-0-b8f496d71664%40kernel.org?part=4
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> net/mptcp/pm.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> index 5e499ec1c50a..e46abbda7d27 100644
> --- a/net/mptcp/pm.c
> +++ b/net/mptcp/pm.c
> @@ -462,10 +462,10 @@ bool mptcp_pm_announced_alloc(struct mptcp_sock *msk,
>
> 	add_entry->addr = *addr;
> 	add_entry->sock = msk;
> -	add_entry->retrans_times = 0;
>
> 	timer_setup(&add_entry->timer, mptcp_pm_add_addr_timer, 0);
> reset_timer:
> +	add_entry->retrans_times = 0;
> 	add_entry->timer_done = false;
> 	timeout = mptcp_adjust_add_addr_timeout(msk);
> 	if (timeout)
>
> ---
> base-commit: 0715f5ba093a581def25b88da61c987b1719bc6d
> change-id: 20260805-mptcp-pm-reset-retrans_time-8894830b0bd7

Looks good to me, thanks for the fix.

Reviewed-by: Mat Martineau <martineau@kernel.org>

Re: [PATCH mptcp-net] mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

[Matthieu Baerts]

Hi Mat,

On 14/08/2026 03:22, Mat Martineau wrote:
> On Wed, 5 Aug 2026, Matthieu Baerts (NGI0) wrote:
> 
>> When an ADD_ADDR entry is reused, the timer is re-armed, because the
>> goal is to re-announce an ADD_ADDR, and eventually retransmit it if
>> needed.
>>
>> In this case, the retransmission counter should be reset as well, so the
>> re-announced address gets its retransmissions back instead of relying on
>> what was left before, and possibly not being able to retransmit it.

(...)

> Looks good to me, thanks for the fix.
Thank you for the review!

Now in our tree:

New patches for t/upstream-net and t/upstream:
- f9ff581a97d0: mptcp: pm: reset retrans_time when ADD_ADDR entry is reused
- Results: 745049d83503..79d7297194ac (export-net)
- Results: d536472a82d1..199ed983c1f7 (export)

Tests are now in progress:

- export-net:
https://github.com/multipath-tcp/mptcp_net-next/commit/9bf507e411f4bc32904bdf34fdbe9e9406e9d025/checks
- export:
https://github.com/multipath-tcp/mptcp_net-next/commit/ba6afbce3cb1ec026c104c44bfebe101bbd2ef35/checks

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.