Re: [PATCH mptcp-next v3 0/7] mptcp: add bpf_setsockopt support

[gang.yan@linux.dev]

July 27, 2026 at 2:04 PM, "Geliang Tang" <geliang@kernel.org mailto:geliang@kernel.org?to=%22Geliang%20Tang%22%20%3Cgeliang%40kernel.org%3E > wrote:


> 
> Hi Gang,
> 
> On Mon, 2026-07-27 at 10:28 +0800, Gang Yan wrote:
> 
> > 
> > From: Gang Yan <yangang@kylinos.cn>
> >  
> >  Hi, Matt, Geliang, Paolo
> >  
> >  Patch 3-4 have been reviewed by Paolo before, and ready for merge
> >  [1][2].
> > 
> Do not put unrelated code into a single series. This series is for
> adding bpf_setsockopt support; other patches do not belong here.
> 
> > 
> > Changelog:
> >  v3:
> >    - Patch 2 keeps the mptcp_setsockopt_all_sf as Geliang suggested.
> > 
> I recommend that you hold off on sending this patch for now: "Let's
> wait until IPV6_TCLASS is merged before posting this patch." Rather
> than keeping an unused mptcp_setsockopt_all_sf.
> 
> Do not send code that has not passed compilation to the mailing list.
>

Hi Geliang
 
I sincerely apologize for the noise. I'll drop this patch and wait for the IPV6_TCLASS merge.

Thanks
Gang
> > 
> > v2:
> >    - Patches 1 and 2 are new in this series; they address TCP_MAXSEG
> >      handling in the bpf_setsockopt() path.
> >    - Patch 4 adds an early return to fix msk->sk_rcvlowat being
> >      unexpectedly modified, an issue seen in v1.
> >    - Patch 5 makes the hook safe for the non-tcp master socket: it
> >  guards
> >      bpf_sock_ops_cb_flags_set() with sk_is_tcp() to prevent out-of-
> >  bounds
> >      heap reads/writes through tcp_sk(sk)->bpf_sock_ops_cb_flags, and
> >  does
> >      not set is_locked_tcp_sock for the msk (unlike tcp_call_bpf()).
> >  That
> >      flag authorizes the verifier's direct tcp_sock-offset field
> >  accesses;
> >      since the msk is not a tcp_sock, leaving it at the default 0 is
> >  safe.
> >  
> >  v1:
> >    Link:
> >  https://patchwork.kernel.org/project/mptcp/cover/20260713095735.1222033-1-gang.yan@linux.dev/
> >  
> >  [1]
> >  https://patchwork.kernel.org/project/mptcp/patch/20260522-sockopt_lock-v5-2-108629a46e98@kylinos.cn/
> >  [2]
> >  https://patchwork.kernel.org/project/mptcp/patch/20260522-sockopt_lock-v5-4-108629a46e98@kylinos.cn/
> >  
> >  Gang Yan (7):
> >    mptcp: drop unused @max arg of __mptcp_setsockopt_set_val
> >    mptcp: take TCP_MAXSEG handling into __mptcp_setsockopt_set_val
> >    mptcp: use sockopt_lock/release_sock in sockopt
> >    mptcp: reject sockopt requiring ssks' lock in BPF context
> >    mptcp: enable bpf_setsockopt on the master socket
> >    mptcp: add TCP_CONNECT_CB sock_ops hook
> >    selftests: bpf: verify mptcp bpf_setsockopt from TCP_CONNECT_CB
> >  
> >   include/net/mptcp.h                           |   9 ++
> >   net/core/filter.c                             |  10 ++
> >   net/ipv4/tcp.c                                |   1 +
> >   net/mptcp/protocol.c                          |   6 +
> >   net/mptcp/protocol.h                          |  29 ++++
> >   net/mptcp/sockopt.c                           | 127 +++++++++++-----
> >  --
> >   .../testing/selftests/bpf/prog_tests/mptcp.c  |  61 +++++++++
> >   .../selftests/bpf/progs/mptcp_setsockopt.c    |  32 +++++
> >   8 files changed, 223 insertions(+), 52 deletions(-)
> >   create mode 100644
> >  tools/testing/selftests/bpf/progs/mptcp_setsockopt.c
> >
>