Re: [PATCH net v3] mptcp: only set DATA_FIN when a mapping is present

On Fri, Jul 10, 2026 at 12:19 PM Matthieu Baerts [off-list ref] wrote:

I tried to reproduce it on my side using packetdrill-mptcp [1], but I
was not able to test with KMSAN: my kernel boot, but is stuck when KMSAN
is enabled... By chance, if you can try this reproducer on your side,
with and without your patched kernel, that would be great :)

[1] https://github.com/multipath-tcp/packetdrill/pull/203

Can you try with more RAM and make sure that you have these set too?

CONFIG_CRYPTO_USER_API=y
CONFIG_CRYPTO_USER_API_HASH=y

I was able to get your PR #203 test to trigger after using -m 8G +
AF_ALG under vng

  BUG: KMSAN: uninit-value in mptcp_incoming_options+0x1da9
   mptcp_incoming_options
   tcp_data_queue
   tcp_rcv_established
   tcp_v4_do_rcv
   tcp_v4_rcv
   ip_protocol_deliver_rcu
   ip_local_deliver_finish
   ip_local_deliver
   ip_rcv

Thanks,
Mike