Re: [PATCH mptcp-net 2/2] Squash-to: "mptcp: do not reschedule the RTX timer for fallback sockets"

[Paolo Abeni <pabeni@redhat.com>]

On 8/26/26 2:38 PM, Matthieu Baerts wrote:
> On 26/08/2026 12:13, Paolo Abeni wrote:
>> Sashiko noted that the 'RTX disabled' status is carried over
>> across connect() failures, potentially to subsequent successful connect()
>> or listen().
>>
>> Explicitly control the RTX enabling status across the whole msk life-cycle.
>> To make the code more straight forward switch the newly introduced flag
>> semantic.
> 
> Thank you for looking at this!
> 
>> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
>> ---
>>  net/mptcp/protocol.c | 8 +++++---
>>  net/mptcp/protocol.h | 2 +-
>>  2 files changed, 6 insertions(+), 4 deletions(-)
>>
>> diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
>> index 1e7e59d497c5..db745d9dde59 100644
>> --- a/net/mptcp/protocol.c
>> +++ b/net/mptcp/protocol.c
> 
> (...)
> 
>> @@ -3363,7 +3363,7 @@ void mptcp_set_state(struct sock *sk, int state)
>>  		 */
>>  		break;
>>  	case TCP_CLOSE:
>> -		set_bit(MPTCP_RTX_DISABLED, &mptcp_sk(sk)->flags);
>> +		clear_bit(MPTCP_RTX_ENABLED, &mptcp_sk(sk)->flags);
> 
> Could this be moved to mptcp_disconnect()? Or we prefer not, to stop
> ASAP for some cases? (but I guess most of these cases switch to close
> before transitioning to ESTABLISHED, no?)
Why do you want to move the above to mptcp_disconnect()? It's better to
prevent the rtx timer from taking action after the msk moved to close
for any reason. IIRC we had a few syzkaller splat in the past without
such check.

/P