Commit graph

1,395 commits

Author SHA1 Message Date
Matthieu Baerts (NGI0)
dccf46179d mptcp: only reset subflow errors when propagated
Some subflow socket errors need to be reported to the MPTCP socket: the
initial subflow connect (MP_CAPABLE), and the ones from the fallback
sockets. The others are not propagated.

The issue is that sock_error() was used to retrieve the error, which was
also resetting the sk_err field. Because of that, when notifying the
userspace about subflow close events later on from the MPTCP worker, the
ssk->sk_err field was always 0.

Now, the error (sk_err) is only reset when propagating it to the msk.

Fixes: 15cc104533 ("mptcp: deliver ssk errors to msk")
Cc: stable@vger.kernel.org
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260127-net-mptcp-dup-nl-events-v1-3-7f71e1bc4feb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-28 20:58:50 -08:00
Matthieu Baerts (NGI0)
280d654324 mptcp: avoid dup SUB_CLOSED events after disconnect
In case of subflow disconnect(), which can also happen with the first
subflow in case of errors like timeout or reset, mptcp_subflow_ctx_reset
will reset most fields from the mptcp_subflow_context structure,
including close_event_done. Then, when another subflow is closed, yet
another SUB_CLOSED event for the disconnected initial subflow is sent.
Because of the previous reset, there are no source address and
destination port.

A solution is then to also check the subflow's local id: it shouldn't be
negative anyway.

Another solution would be not to reset subflow->close_event_done at
disconnect time, but when reused. But then, probably the whole reset
could be done when being reused. Let's not change this logic, similar
to TCP with tcp_disconnect().

Fixes: d82809b6c5 ("mptcp: avoid duplicated SUB_CLOSED events")
Cc: stable@vger.kernel.org
Reported-by: Marco Angaroni <marco.angaroni@italtel.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/603
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260127-net-mptcp-dup-nl-events-v1-1-7f71e1bc4feb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-28 20:58:50 -08:00
Eric Dumazet
e2a9eeb69f mptcp: fix race in mptcp_pm_nl_flush_addrs_doit()
syzbot and Eulgyu Kim reported crashes in mptcp_pm_nl_get_local_id()
and/or mptcp_pm_nl_is_backup()

Root cause is list_splice_init() in mptcp_pm_nl_flush_addrs_doit()
which is not RCU ready.

list_splice_init_rcu() can not be called here while holding pernet->lock
spinlock.

Many thanks to Eulgyu Kim for providing a repro and testing our patches.

Fixes: 141694df65 ("mptcp: remove address when netlink flushes addrs")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+5498a510ff9de39d37da@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6970a46d.a00a0220.3ad28e.5cf0.GAE@google.com/T/
Reported-by: Eulgyu Kim <eulgyukim@snu.ac.kr>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/611
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260124-net-mptcp-race_nl_flush_addrs-v3-1-b2dc1b613e9d@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-26 19:32:59 -08:00
Paolo Abeni
86730ac255 mptcp: ensure context reset on disconnect()
After the blamed commit below, if the MPC subflow is already in TCP_CLOSE
status or has fallback to TCP at mptcp_disconnect() time,
mptcp_do_fastclose() skips setting the `send_fastclose flag` and the later
__mptcp_close_ssk() does not reset anymore the related subflow context.

Any later connection will be created with both the `request_mptcp` flag
and the msk-level fallback status off (it is unconditionally cleared at
MPTCP disconnect time), leading to a warning in subflow_data_ready():

  WARNING: CPU: 26 PID: 8996 at net/mptcp/subflow.c:1519 subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13))
  Modules linked in:
  CPU: 26 UID: 0 PID: 8996 Comm: syz.22.39 Not tainted 6.18.0-rc7-05427-g11fc074f6c36 #1 PREEMPT(voluntary)
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  RIP: 0010:subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13))
  Code: 90 0f 0b 90 90 e9 04 fe ff ff e8 b7 1e f5 fe 89 ee bf 07 00 00 00 e8 db 19 f5 fe 83 fd 07 0f 84 35 ff ff ff e8 9d 1e f5 fe 90 <0f> 0b 90 e9 27 ff ff ff e8 8f 1e f5 fe 4c 89 e7 48 89 de e8 14 09
  RSP: 0018:ffffc9002646fb30 EFLAGS: 00010293
  RAX: 0000000000000000 RBX: ffff88813b218000 RCX: ffffffff825c8435
  RDX: ffff8881300b3580 RSI: ffffffff825c8443 RDI: 0000000000000005
  RBP: 000000000000000b R08: ffffffff825c8435 R09: 000000000000000b
  R10: 0000000000000005 R11: 0000000000000007 R12: ffff888131ac0000
  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  FS:  00007f88330af6c0(0000) GS:ffff888a93dd2000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f88330aefe8 CR3: 000000010ff59000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   tcp_data_ready (net/ipv4/tcp_input.c:5356)
   tcp_data_queue (net/ipv4/tcp_input.c:5445)
   tcp_rcv_state_process (net/ipv4/tcp_input.c:7165)
   tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1955)
   __release_sock (include/net/sock.h:1158 (discriminator 6) net/core/sock.c:3180 (discriminator 6))
   release_sock (net/core/sock.c:3737)
   mptcp_sendmsg (net/mptcp/protocol.c:1763 net/mptcp/protocol.c:1857)
   inet_sendmsg (net/ipv4/af_inet.c:853 (discriminator 7))
   __sys_sendto (net/socket.c:727 (discriminator 15) net/socket.c:742 (discriminator 15) net/socket.c:2244 (discriminator 15))
   __x64_sys_sendto (net/socket.c:2247)
   do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
  RIP: 0033:0x7f883326702d

Address the issue setting an explicit `fastclosing` flag at fastclose
time, and checking such flag after mptcp_do_fastclose().

Fixes: ae15506024 ("mptcp: fix duplicate reset on fastclose")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v1-2-d1f9fd1c36c8@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-23 09:12:25 +01:00
Paolo Abeni
71154bbe49 mptcp: fallback earlier on simult connection
Syzkaller reports a simult-connect race leading to inconsistent fallback
status:

  WARNING: CPU: 3 PID: 33 at net/mptcp/subflow.c:1515 subflow_data_ready+0x40b/0x7c0 net/mptcp/subflow.c:1515
  Modules linked in:
  CPU: 3 UID: 0 PID: 33 Comm: ksoftirqd/3 Not tainted syzkaller #0 PREEMPT(full)
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
  RIP: 0010:subflow_data_ready+0x40b/0x7c0 net/mptcp/subflow.c:1515
  Code: 89 ee e8 78 61 3c f6 40 84 ed 75 21 e8 8e 66 3c f6 44 89 fe bf 07 00 00 00 e8 c1 61 3c f6 41 83 ff 07 74 09 e8 76 66 3c f6 90 <0f> 0b 90 e8 6d 66 3c f6 48 89 df e8 e5 ad ff ff 31 ff 89 c5 89 c6
  RSP: 0018:ffffc900006cf338 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffff888031acd100 RCX: ffffffff8b7f2abf
  RDX: ffff88801e6ea440 RSI: ffffffff8b7f2aca RDI: 0000000000000005
  RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000007
  R10: 0000000000000004 R11: 0000000000002c10 R12: ffff88802ba69900
  R13: 1ffff920000d9e67 R14: ffff888046f81800 R15: 0000000000000004
  FS:  0000000000000000(0000) GS:ffff8880d69bc000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000560fc0ca1670 CR3: 0000000032c3a000 CR4: 0000000000352ef0
  Call Trace:
   <TASK>
   tcp_data_queue+0x13b0/0x4f90 net/ipv4/tcp_input.c:5197
   tcp_rcv_state_process+0xfdf/0x4ec0 net/ipv4/tcp_input.c:6922
   tcp_v6_do_rcv+0x492/0x1740 net/ipv6/tcp_ipv6.c:1672
   tcp_v6_rcv+0x2976/0x41e0 net/ipv6/tcp_ipv6.c:1918
   ip6_protocol_deliver_rcu+0x188/0x1520 net/ipv6/ip6_input.c:438
   ip6_input_finish+0x1e4/0x4b0 net/ipv6/ip6_input.c:489
   NF_HOOK include/linux/netfilter.h:318 [inline]
   NF_HOOK include/linux/netfilter.h:312 [inline]
   ip6_input+0x105/0x2f0 net/ipv6/ip6_input.c:500
   dst_input include/net/dst.h:471 [inline]
   ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
   NF_HOOK include/linux/netfilter.h:318 [inline]
   NF_HOOK include/linux/netfilter.h:312 [inline]
   ipv6_rcv+0x264/0x650 net/ipv6/ip6_input.c:311
   __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:5979
   __netif_receive_skb+0x1d/0x160 net/core/dev.c:6092
   process_backlog+0x442/0x15e0 net/core/dev.c:6444
   __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7494
   napi_poll net/core/dev.c:7557 [inline]
   net_rx_action+0xa9f/0xfe0 net/core/dev.c:7684
   handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
   run_ksoftirqd kernel/softirq.c:968 [inline]
   run_ksoftirqd+0x3a/0x60 kernel/softirq.c:960
   smpboot_thread_fn+0x3f7/0xae0 kernel/smpboot.c:160
   kthread+0x3c2/0x780 kernel/kthread.c:463
   ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
   </TASK>

The TCP subflow can process the simult-connect syn-ack packet after
transitioning to TCP_FIN1 state, bypassing the MPTCP fallback check,
as the sk_state_change() callback is not invoked for * -> FIN_WAIT1
transitions.

That will move the msk socket to an inconsistent status and the next
incoming data will hit the reported splat.

Close the race moving the simult-fallback check at the earliest possible
stage - that is at syn-ack generation time.

About the fixes tags: [2] was supposed to also fix this issue introduced
by [3]. [1] is required as a dependence: it was not explicitly marked as
a fix, but it is one and it has already been backported before [3]. In
other words, this commit should be backported up to [3], including [2]
and [1] if that's not already there.

Fixes: 23e89e8ee7 ("tcp: Don't drop SYN+ACK for simultaneous connect().") [1]
Fixes: 4fd19a3070 ("mptcp: fix inconsistent state on fastopen race") [2]
Fixes: 1e777f39b4 ("mptcp: add MSG_FASTOPEN sendmsg flag support") [3]
Cc: stable@vger.kernel.org
Reported-by: syzbot+0ff6b771b4f7a5bce83b@syzkaller.appspotmail.com
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/586
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251212-net-mptcp-subflow_data_ready-warn-v1-1-d1f9fd1c36c8@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-12-23 09:12:25 +01:00
Paolo Abeni
ffb8c27b05 mptcp: avoid deadlock on fallback while reinjecting
Jakub reported an MPTCP deadlock at fallback time:

 WARNING: possible recursive locking detected
 6.18.0-rc7-virtme #1 Not tainted
 --------------------------------------------
 mptcp_connect/20858 is trying to acquire lock:
 ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_try_fallback+0xd8/0x280

 but task is already holding lock:
 ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&msk->fallback_lock);
   lock(&msk->fallback_lock);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 3 locks held by mptcp_connect/20858:
  #0: ff1100001da18290 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x114/0x1bc0
  #1: ff1100001db40fd0 (k-sk_lock-AF_INET#2){+.+.}-{0:0}, at: __mptcp_retrans+0x2cb/0xaa0
  #2: ff1100001da18b60 (&msk->fallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0

 stack backtrace:
 CPU: 0 UID: 0 PID: 20858 Comm: mptcp_connect Not tainted 6.18.0-rc7-virtme #1 PREEMPT(full)
 Hardware name: Bochs, BIOS Bochs 01/01/2011
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6f/0xa0
  print_deadlock_bug.cold+0xc0/0xcd
  validate_chain+0x2ff/0x5f0
  __lock_acquire+0x34c/0x740
  lock_acquire.part.0+0xbc/0x260
  _raw_spin_lock_bh+0x38/0x50
  __mptcp_try_fallback+0xd8/0x280
  mptcp_sendmsg_frag+0x16c2/0x3050
  __mptcp_retrans+0x421/0xaa0
  mptcp_release_cb+0x5aa/0xa70
  release_sock+0xab/0x1d0
  mptcp_sendmsg+0xd5b/0x1bc0
  sock_write_iter+0x281/0x4d0
  new_sync_write+0x3c5/0x6f0
  vfs_write+0x65e/0xbb0
  ksys_write+0x17e/0x200
  do_syscall_64+0xbb/0xfd0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
 RIP: 0033:0x7fa5627cbc5e
 Code: 4d 89 d8 e8 14 bd 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 <c9> c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa
 RSP: 002b:00007fff1fe14700 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fa5627cbc5e
 RDX: 0000000000001f9c RSI: 00007fff1fe16984 RDI: 0000000000000005
 RBP: 00007fff1fe14710 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff1fe16920
 R13: 0000000000002000 R14: 0000000000001f9c R15: 0000000000001f9c

The packet scheduler could attempt a reinjection after receiving an
MP_FAIL and before the infinite map has been transmitted, causing a
deadlock since MPTCP needs to do the reinjection atomically from WRT
fallback.

Address the issue explicitly avoiding the reinjection in the critical
scenario. Note that this is the only fallback critical section that
could potentially send packets and hit the double-lock.

Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://netdev-ctrl.bots.linux.dev/logs/vmksft/mptcp-dbg/results/412720/1-mptcp-join-sh/stderr
Fixes: f8a1d9b18c ("mptcp: make fallback action and fallback decision atomic")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-4-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-08 23:54:03 -08:00
Paolo Abeni
2ea6190f42 mptcp: schedule rtx timer only after pushing data
The MPTCP protocol usually schedule the retransmission timer only
when there is some chances for such retransmissions to happen.

With a notable exception: __mptcp_push_pending() currently schedule
such timer unconditionally, potentially leading to unnecessary rtx
timer expiration.

The issue is present since the blamed commit below but become easily
reproducible after commit 27b0e701d3 ("mptcp: drop bogus optimization
in __mptcp_check_push()")

Fixes: 33d41c9cd7 ("mptcp: more accurate timeout")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-3-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-08 23:54:03 -08:00
Matthieu Baerts (NGI0)
0ace3297a7 mptcp: pm: ignore unknown endpoint flags
Before this patch, the kernel was saving any flags set by the userspace,
even unknown ones. This doesn't cause critical issues because the kernel
is only looking at specific ones. But on the other hand, endpoints dumps
could tell the userspace some recent flags seem to be supported on older
kernel versions.

Instead, ignore all unknown flags when parsing them. By doing that, the
userspace can continue to set unsupported flags, but it has a way to
verify what is supported by the kernel.

Note that it sounds better to continue accepting unsupported flags not
to change the behaviour, but also that eases things on the userspace
side by adding "optional" endpoint types only supported by newer kernel
versions without having to deal with the different kernel versions.

A note for the backports: there will be conflicts in mptcp.h on older
versions not having the mentioned flags, the new line should still be
added last, and the '5' needs to be adapted to have the same value as
the last entry.

Fixes: 01cacb00b3 ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-1-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-08 23:54:02 -08:00
Eric Biggers
e9e5047df9 mptcp: select CRYPTO_LIB_UTILS instead of CRYPTO
Since the only crypto functions used by the mptcp code are the SHA-256
library functions and crypto_memneq(), select only the options needed
for those: CRYPTO_LIB_SHA256 and CRYPTO_LIB_UTILS.

Previously, CRYPTO was selected instead of CRYPTO_LIB_UTILS.  That does
pull in CRYPTO_LIB_UTILS as well, but it's unnecessarily broad.

Years ago, the CRYPTO_LIB_* options were visible only when CRYPTO.  That
may be another reason why CRYPTO is selected here.  However, that was
fixed years ago, and the libraries can now be selected directly.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Link: https://patch.msgid.link/20251204054417.491439-1-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-08 23:44:16 -08:00
Jakub Kicinski
db4029859d Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Conflicts:

net/xdp/xsk.c
  0ebc27a4c6 ("xsk: avoid data corruption on cq descriptor number")
  8da7bea7db ("xsk: add indirect call for xsk_destruct_skb")
  30ed05adca ("xsk: use a smaller new lock for shared pool case")
https://lore.kernel.org/20251127105450.4a1665ec@canb.auug.org.au
https://lore.kernel.org/eb4eee14-7e24-4d1b-b312-e9ea738fefee@kernel.org

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-27 12:19:08 -08:00
Kuniyuki Iwashima
f07f4ea53e mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in mptcp_do_fastclose().
syzbot reported divide-by-zero in __tcp_select_window() by
MPTCP socket. [0]

We had a similar issue for the bare TCP and fixed in commit
499350a5a6 ("tcp: initialize rcv_mss to TCP_MIN_MSS instead
of 0").

Let's apply the same fix to mptcp_do_fastclose().

[0]:
Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6068 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__tcp_select_window+0x824/0x1320 net/ipv4/tcp_output.c:3336
Code: ff ff ff 44 89 f1 d3 e0 89 c1 f7 d1 41 01 cc 41 21 c4 e9 a9 00 00 00 e8 ca 49 01 f8 e9 9c 00 00 00 e8 c0 49 01 f8 44 89 e0 99 <f7> 7c 24 1c 41 29 d4 48 bb 00 00 00 00 00 fc ff df e9 80 00 00 00
RSP: 0018:ffffc90003017640 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88807b469e40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003017730 R08: ffff888033268143 R09: 1ffff1100664d028
R10: dffffc0000000000 R11: ffffed100664d029 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  000055557faa0500(0000) GS:ffff888126135000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f64a1912ff8 CR3: 0000000072122000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 tcp_select_window net/ipv4/tcp_output.c:281 [inline]
 __tcp_transmit_skb+0xbc7/0x3aa0 net/ipv4/tcp_output.c:1568
 tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]
 tcp_send_active_reset+0x2d1/0x5b0 net/ipv4/tcp_output.c:3836
 mptcp_do_fastclose+0x27e/0x380 net/mptcp/protocol.c:2793
 mptcp_disconnect+0x238/0x710 net/mptcp/protocol.c:3253
 mptcp_sendmsg_fastopen+0x2f8/0x580 net/mptcp/protocol.c:1776
 mptcp_sendmsg+0x1774/0x1980 net/mptcp/protocol.c:1855
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0xe5/0x270 net/socket.c:742
 __sys_sendto+0x3bd/0x520 net/socket.c:2244
 __do_sys_sendto net/socket.c:2251 [inline]
 __se_sys_sendto net/socket.c:2247 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2247
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f66e998f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffff9acedb8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f66e9be5fa0 RCX: 00007f66e998f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffff9acee10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f66e9be5fa0 R14: 00007f66e9be5fa0 R15: 0000000000000006
 </TASK>

Fixes: ae15506024 ("mptcp: fix duplicate reset on fastclose")
Reported-by: syzbot+3a92d359bc2ec6255a33@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/69260882.a70a0220.d98e3.00b4.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251125195331.309558-1-kuniyu@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2025-11-27 13:10:16 +01:00
Paolo Abeni
27fd028601 mptcp: clear scheduled subflows on retransmit
When __mptcp_retrans() kicks-in, it schedules one or more subflows for
retransmission, but such subflows could be actually left alone if there
is no more data to retransmit and/or in case of concurrent fallback.

Scheduled subflows could be processed much later in time, i.e. when new
data will be transmitted, leading to bad subflow selection.

Explicitly clear all scheduled subflows before leaving the
retransmission function.

Fixes: ee2708aeda ("mptcp: use get_retrans wrapper")
Cc: stable@vger.kernel.org
Reported-by: Filip Pokryvka <fpokryvk@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251125-net-mptcp-clear-sched-rtx-v1-1-1cea4ad2165f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-26 18:24:35 -08:00
Eric Dumazet
9a5e5334ad tcp: remove icsk->icsk_retransmit_timer
Now sk->sk_timer is no longer used by TCP keepalive, we can use
its storage for TCP and MPTCP retransmit timers for better
cache locality.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:29 -08:00
Eric Dumazet
08dfe37023 tcp: introduce icsk->icsk_keepalive_timer
sk->sk_timer has been used for TCP keepalives.

Keepalive timers are not in fast path, we want to use sk->sk_timer
storage for retransmit timers, for better cache locality.

Create icsk->icsk_keepalive_timer and change keepalive
code to no longer use sk->sk_timer.

Added space is reclaimed in the following patch.

This includes changes to MPTCP, which was also using sk_timer.

Alias icsk->mptcp_tout_timer and icsk->icsk_keepalive_timer
for inet_sk_diag_fill() sake.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:29 -08:00
Eric Dumazet
3a6e8fd0bf tcp: rename icsk_timeout() to tcp_timeout_expires()
In preparation of sk->tcp_timeout_timer introduction,
rename icsk_timeout() helper and change its argument to plain
'const struct sock *sk'.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251124175013.1473655-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:28:28 -08:00
Asbjørn Sloth Tønnesen
68e83f3472 tools: ynl-gen: add regeneration comment
Add a comment on regeneration to the generated files.

The comment is placed after the YNL-GEN line[1], as to not interfere
with ynl-regen.sh's detection logic.

[1] and after the optional YNL-ARG line.

Link: https://lore.kernel.org/r/aR5m174O7pklKrMR@zx2c4.com/
Suggested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251120174429.390574-3-ast@fiberby.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-25 19:20:42 -08:00
Paolo Abeni
6228efe0cc mptcp: leverage the backlog for RX packet processing
When the msk socket is owned or the msk receive buffer is full,
move the incoming skbs in a msk level backlog list. This avoid
traversing the joined subflows and acquiring the subflow level
socket lock at reception time, improving the RX performances.

When processing the backlog, use the fwd alloc memory borrowed from
the incoming subflow. skbs exceeding the msk receive space are
not dropped; instead they are kept into the backlog until the receive
buffer is freed. Dropping packets already acked at the TCP level is
explicitly discouraged by the RFC and would corrupt the data stream
for fallback sockets.

Special care is needed to avoid adding skbs to the backlog of a closed
msk and to avoid leaving dangling references into the backlog
at subflow closing time.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-14-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:43 -08:00
Paolo Abeni
ee458a3f31 mptcp: introduce mptcp-level backlog
We are soon using it for incoming data processing.
MPTCP can't leverage the sk_backlog, as the latter is processed
before the release callback, and such callback for MPTCP releases
and re-acquire the socket spinlock, breaking the sk_backlog processing
assumption.

Add a skb backlog list inside the mptcp sock struct, and implement
basic helper to transfer packet to and purge such list.

Packets in the backlog are memory accounted and still use the incoming
subflow receive memory, to allow back-pressure. The backlog size is
implicitly bounded to the sum of subflows rcvbuf.

When a subflow is closed, references from the backlog to such sock
are removed.

No packet is currently added to the backlog, so no functional changes
intended here.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-13-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:43 -08:00
Paolo Abeni
9db5b3cec4 mptcp: borrow forward memory from subflow
In the MPTCP receive path, we release the subflow allocated fwd
memory just to allocate it again shortly after for the msk.

That could increases the failures chances, especially when we will
add backlog processing, with other actions could consume the just
released memory before the msk socket has a chance to do the
rcv allocation.

Replace the skb_orphan() call with an open-coded variant that
explicitly borrows, the fwd memory from the subflow socket instead
of releasing it.

The borrowed memory does not have PAGE_SIZE granularity; rounding to
the page size will make the fwd allocated memory higher than what is
strictly required and could make the incoming subflow fwd mem
consistently negative. Instead, keep track of the accumulated frag and
borrow the full page at subflow close time.

This allow removing the last drop in the TCP to MPTCP transition and
the associated, now unused, MIB.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-12-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
0eeb372dee mptcp: handle first subflow closing consistently
Currently, as soon as the PM closes a subflow, the msk stops accepting
data from it, even if the TCP socket could be still formally open in the
incoming direction, with the notable exception of the first subflow.

The root cause of such behavior is that code currently piggy back two
separate semantic on the subflow->disposable bit: the subflow context
must be released and that the subflow must stop accepting incoming
data.

The first subflow is never disposed, so it also never stop accepting
incoming data. Use a separate bit to mark the latter status and set such
bit in __mptcp_close_ssk() for all subflows.

Beyond making per subflow behaviour more consistent this will also
simplify the next patch.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-11-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
38a4a469c8 mptcp: drop the __mptcp_data_ready() helper
It adds little clarity and there is a single user of such helper,
just inline it in the caller.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-10-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
9d82959603 mptcp: make mptcp_destroy_common() static
Such function is only used inside protocol.c, there is no need
to expose it to the whole stack.

Note that the function definition most be moved earlier to avoid
forward declaration.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-9-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
48a395605e mptcp: do not miss early first subflow close event notification
The MPTCP protocol is not currently emitting the NL event when the first
subflow is closed before msk accept() time.

By replacing the in use close helper is such scenario, implicitly introduce
the missing notification. Note that in such scenario we want to be sure
that mptcp_close_ssk() will not trigger any PM work, move the msk state
change update earlier, so that the previous patch will offer such
guarantee.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-8-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
2ca1b8926f mptcp: ensure the kernel PM does not take action too late
The PM hooks can currently take place when the msk is already shutting
down. Subflow creation will fail, thanks to the existing check at join
time, but we can entirely avoid starting the to be failed operations.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-7-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:42 -08:00
Paolo Abeni
2834f8edd7 mptcp: cleanup fallback dummy mapping generation
MPTCP currently access ack_seq outside the msk socket log scope to
generate the dummy mapping for fallback socket. Soon we are going
to introduce backlog usage and even for fallback socket the ack_seq
value will be significantly off outside of the msk socket lock scope.

Avoid relying on ack_seq for dummy mapping generation, using instead
the subflow sequence number. Note that in case of disconnect() and
(re)connect() we must ensure that any previous state is re-set.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-6-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:41 -08:00
Paolo Abeni
85f22b8e1e mptcp: cleanup fallback data fin reception
MPTCP currently generate a dummy data_fin for fallback socket
when the fallback subflow has completed data reception using
the current ack_seq.

We are going to introduce backlog usage for the msk soon, even
for fallback sockets: the ack_seq value will not match the most recent
sequence number seen by the fallback subflow socket, as it will ignore
data_seq sitting in the backlog.

Instead use the last map sequence number to set the data_fin,
as fallback (dummy) map sequences are always in sequence.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Tested-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-5-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:41 -08:00
Paolo Abeni
68c7c38671 mptcp: fix memcg accounting for passive sockets
The passive sockets never got proper memcg accounting: the msk
socket is associated with the memcg at accept time, but the
passive subflows never got it right.

At accept time, traverse the subflows list and associate each of them
with the msk memcg, and try to do the same at join completion time, if
the msk has been already accepted.

Fixes: cf7da0d66c ("mptcp: Create SUBFLOW socket for incoming connections")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/298
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/597
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-4-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:41 -08:00
Paolo Abeni
e777a7fb06 mptcp: grafting MPJ subflow earlier
Later patches need to ensure that all MPJ subflows are grafted to the
msk socket before accept() completion.

Currently the grafting happens under the msk socket lock: potentially
at msk release_cb time which make satisfying the above condition a bit
tricky.

Move the MPJ subflow grafting earlier, under the msk data lock, so that
we can use such lock as a synchronization point.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-3-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:41 -08:00
Paolo Abeni
bd92dd8e03 mptcp: factor-out cgroup data inherit helper
MPTCP will soon need the same functionality for passive sockets,
factor them out in a common helper. No functional change intended.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251121-net-next-mptcp-memcg-backlog-imp-v1-2-1f34b6c1e0b1@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-24 19:49:41 -08:00
Jakub Kicinski
9e203721ec Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.18-rc7).

No conflicts, adjacent changes:

tools/testing/selftests/net/af_unix/Makefile
  e1bb28bf13 ("selftest: af_unix: Add test for SO_PEEK_OFF.")
  45a1cd8346 ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-20 09:13:26 -08:00
Linus Torvalds
8e621c9a33 Including fixes from IPsec and wireless.
Previous releases - regressions:
 
  - prevent NULL deref in generic_hwtstamp_ioctl_lower(),
    newer APIs don't populate all the pointers in the request
 
  - phylink: add missing supported link modes for the fixed-link
 
  - mptcp: fix false positive warning in mptcp_pm_nl_rm_addr
 
 Previous releases - always broken:
 
  - openvswitch: remove never-working support for setting NSH fields
 
  - xfrm: number of fixes for error paths of xfrm_state creation/
    modification/deletion
 
  - xfrm: fixes for offload
    - fix the determination of the protocol of the inner packet
    - don't push locally generated packets directly to L2 tunnel
      mode offloading, they still need processing from the standard
      xfrm path
 
  - mptcp: fix a couple of corner cases in fallback and fastclose
    handling
 
  - wifi: rtw89: hw_scan: prevent connections from getting stuck,
    work around apparent bug in FW by tweaking messages we send
 
  - af_unix: fix duplicate data if PEEK w/ peek_offset needs to wait
 
  - veth: more robust handing of race to avoid txq getting stuck
 
  - eth: ps3_gelic_net: handle skb allocation failures
 
 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEE6jPA+I1ugmIBA4hXMUZtbf5SIrsFAmkfQv8ACgkQMUZtbf5S
 IruptQ//aa3wFISt/xfCxaygNnQAL1gxWbKg15cLnv88S5r5wrh+Mf/r+qHkT0IG
 qaxPToztcTKNGzRqMI/7x/OEXjCdfEmJtNcb5JfYRxGkYVcje81bhHrxZN+nLLcj
 jx1xD7rXCjfFNDVFSl+OzQkoTZtfGphX+JgCTKLPZ8t4qR/UhU1IwYgpoaiK0uCT
 gitXJPHrDGJLHud0ilaXbn+q0ZH9ZU08QSRhsaAq7C6YPafUseEr2fuQYgFr1kkp
 mtzFm84bEnRSneQ5+noVzoc5llbu3vf3Wd9Y5tr5sBaBjh5OpH/kK0kuPy6Lzhvd
 8y05jl8kyASMtRBoTvmpYOdi3xUNbge5AwJN3FIo4KPCmyr1bQoNoQVIivUpoiGz
 Zvv7QcceP7E5057CRuhi06krld/QaScHkmhUododbqJKmL8NWaSoXLRO7oYjB4kU
 1MuAwOJWVpsqnTUEbMw7dHJPZFTqRkLYv6oAmIqb/AWzTcqg9OXjLEc+OzUqWEl6
 mHv/SonSjAM81m3GxCxtNtH2ErKwdMIgI/ado39+KvksKTH1bhN9ZpmuyyktzpCj
 PBn9FVdd7zyct92u5xXtsKVkDWKGyD419Z2lFHC0FaAsNQmPrSqzi+U50pAtie5M
 JWABm8hsSdia4dTDrdldMgM50dzuBd5nSceY7XCqPA8nZ5+Af/8=
 =89Xl
 -----END PGP SIGNATURE-----

Merge tag 'net-6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Including fixes from IPsec and wireless.

  Previous releases - regressions:

   - prevent NULL deref in generic_hwtstamp_ioctl_lower(),
     newer APIs don't populate all the pointers in the request

   - phylink: add missing supported link modes for the fixed-link

   - mptcp: fix false positive warning in mptcp_pm_nl_rm_addr

  Previous releases - always broken:

   - openvswitch: remove never-working support for setting NSH fields

   - xfrm: number of fixes for error paths of xfrm_state creation/
     modification/deletion

   - xfrm: fixes for offload
      - fix the determination of the protocol of the inner packet
      - don't push locally generated packets directly to L2 tunnel
        mode offloading, they still need processing from the standard
        xfrm path

   - mptcp: fix a couple of corner cases in fallback and fastclose
     handling

   - wifi: rtw89: hw_scan: prevent connections from getting stuck,
     work around apparent bug in FW by tweaking messages we send

   - af_unix: fix duplicate data if PEEK w/ peek_offset needs to wait

   - veth: more robust handing of race to avoid txq getting stuck

   - eth: ps3_gelic_net: handle skb allocation failures"

* tag 'net-6.18-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (47 commits)
  vsock: Ignore signal/timeout on connect() if already established
  be2net: pass wrb_params in case of OS2BMC
  l2tp: reset skb control buffer on xmit
  net: dsa: microchip: lan937x: Fix RGMII delay tuning
  selftests: mptcp: add a check for 'add_addr_accepted'
  mptcp: fix address removal logic in mptcp_pm_nl_rm_addr
  selftests: mptcp: join: userspace: longer timeout
  selftests: mptcp: join: endpoints: longer timeout
  selftests: mptcp: join: fastclose: remove flaky marks
  mptcp: fix duplicate reset on fastclose
  mptcp: decouple mptcp fastclose from tcp close
  mptcp: do not fallback when OoO is present
  mptcp: fix premature close in case of fallback
  mptcp: avoid unneeded subflow-level drops
  mptcp: fix ack generation for fallback msk
  wifi: rtw89: hw_scan: Don't let the operating channel be last
  net: phylink: add missing supported link modes for the fixed-link
  selftest: af_unix: Add test for SO_PEEK_OFF.
  af_unix: Read sk_peek_offset() again after sleeping in unix_stream_read_generic().
  net/mlx5: Clean up only new IRQ glue on request_irq() failure
  ...
2025-11-20 08:52:07 -08:00
Gang Yan
92e239e36d mptcp: fix address removal logic in mptcp_pm_nl_rm_addr
Fix inverted WARN_ON_ONCE condition that prevented normal address
removal counter updates. The current code only executes decrement
logic when the counter is already 0 (abnormal state), while
normal removals (counter > 0) are ignored.

Signed-off-by: Gang Yan <yangang@kylinos.cn>
Fixes: 6361139185 ("mptcp: pm: remove '_nl' from mptcp_pm_nl_rm_addr_received")
Cc: stable@vger.kernel.org
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-10-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:15 -08:00
Paolo Abeni
ae15506024 mptcp: fix duplicate reset on fastclose
The CI reports sporadic failures of the fastclose self-tests. The root
cause is a duplicate reset, not carrying the relevant MPTCP option.
In the failing scenario the bad reset is received by the peer before
the fastclose one, preventing the reception of the latter.

Indeed there is window of opportunity at fastclose time for the
following race:

  mptcp_do_fastclose
    __mptcp_close_ssk
      __tcp_close()
        tcp_set_state() [1]
        tcp_send_active_reset() [2]

After [1] the stack will send reset to in-flight data reaching the now
closed port. Such reset may race with [2].

Address the issue explicitly sending a single reset on fastclose before
explicitly moving the subflow to close status.

Fixes: d21f834855 ("mptcp: use fastclose on more edge scenarios")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/596
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-6-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:15 -08:00
Paolo Abeni
fff0c87996 mptcp: decouple mptcp fastclose from tcp close
With the current fastclose implementation, the mptcp_do_fastclose()
helper is in charge of two distinct actions: send the fastclose reset
and cleanup the subflows.

Formally decouple the two steps, ensuring that mptcp explicitly closes
all the subflows after the mentioned helper.

This will make the upcoming fix simpler, and allows dropping the 2nd
argument from mptcp_destroy_common(). The Fixes tag is then the same as
in the next commit to help with the backports.

Fixes: d21f834855 ("mptcp: use fastclose on more edge scenarios")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-5-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:15 -08:00
Paolo Abeni
1bba3f219c mptcp: do not fallback when OoO is present
In case of DSS corruption, the MPTCP protocol tries to avoid the subflow
reset if fallback is possible. Such corruptions happen in the receive
path; to ensure fallback is possible the stack additionally needs to
check for OoO data, otherwise the fallback will break the data stream.

Fixes: e32d262c89 ("mptcp: handle consistently DSS corruption")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/598
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-4-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:14 -08:00
Paolo Abeni
17393fa7b7 mptcp: fix premature close in case of fallback
I'm observing very frequent self-tests failures in case of fallback when
running on a CONFIG_PREEMPT kernel.

The root cause is that subflow_sched_work_if_closed() closes any subflow
as soon as it is half-closed and has no incoming data pending.

That works well for regular subflows - MPTCP needs bi-directional
connectivity to operate on a given subflow - but for fallback socket is
race prone.

When TCP peer closes the connection before the MPTCP one,
subflow_sched_work_if_closed() will schedule the MPTCP worker to
gracefully close the subflow, and shortly after will do another schedule
to inject and process a dummy incoming DATA_FIN.

On CONFIG_PREEMPT kernel, the MPTCP worker can kick-in and close the
fallback subflow before subflow_sched_work_if_closed() is able to create
the dummy DATA_FIN, unexpectedly interrupting the transfer.

Address the issue explicitly avoiding closing fallback subflows on when
the peer is only half-closed.

Note that, when the subflow is able to create the DATA_FIN before the
worker invocation, the worker will change the msk state before trying to
close the subflow and will skip the latter operation as the msk will not
match anymore the precondition in __mptcp_close_subflow().

Fixes: f09b0ad55a ("mptcp: close subflow when receiving TCP+FIN")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-3-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:14 -08:00
Paolo Abeni
4f102d747c mptcp: avoid unneeded subflow-level drops
The rcv window is shared among all the subflows. Currently, MPTCP sync
the TCP-level rcv window with the MPTCP one at tcp_transmit_skb() time.

The above means that incoming data may sporadically observe outdated
TCP-level rcv window and being wrongly dropped by TCP.

Address the issue checking for the edge condition before queuing the
data at TCP level, and eventually syncing the rcv window as needed.

Note that the issue is actually present from the very first MPTCP
implementation, but backports older than the blamed commit below will
range from impossible to useless.

Before:

  $ nstat -n; sleep 1; nstat -z TcpExtBeyondWindow
  TcpExtBeyondWindow              14                 0.0

After:

  $ nstat -n; sleep 1; nstat -z TcpExtBeyondWindow
  TcpExtBeyondWindow              0                  0.0

Fixes: fa3fe2b150 ("mptcp: track window announced to peer")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-2-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:14 -08:00
Paolo Abeni
5e15395f6d mptcp: fix ack generation for fallback msk
mptcp_cleanup_rbuf() needs to know the last most recent, mptcp-level
rcv_wnd sent, and such information is tracked into the msk->old_wspace
field, updated at ack transmission time by mptcp_write_options().

Fallback socket do not add any mptcp options, such helper is never
invoked, and msk->old_wspace value remain stale. That in turn makes
ack generation at recvmsg() time quite random.

Address the issue ensuring mptcp_write_options() is invoked even for
fallback sockets, and just update the needed info in such a case.

The issue went unnoticed for a long time, as mptcp currently overshots
the fallback socket receive buffer autotune significantly. It is going
to change in the near future.

Fixes: e3859603ba ("mptcp: better msk receive window updates")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/594
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251118-net-mptcp-misc-fixes-6-18-rc6-v1-1-806d3781c95f@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-19 20:07:14 -08:00
Eric Dumazet
426358d9be mptcp: fix a race in mptcp_pm_del_add_timer()
mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer)
while another might have free entry already, as reported by syzbot.

Add RCU protection to fix this issue.

Also change confusing add_timer variable with stop_timer boolean.

syzbot report:

BUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616
Read of size 4 at addr ffff8880311e4150 by task kworker/1:1/44

CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Workqueue: events mptcp_worker
Call Trace:
 <TASK>
  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:378 [inline]
  print_report+0xca/0x240 mm/kasan/report.c:482
  kasan_report+0x118/0x150 mm/kasan/report.c:595
  __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616
  sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631
  mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362
  mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174
  tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361
  tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441
  tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931
  tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374
  ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205
  ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239
  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
  __netif_receive_skb_one_core net/core/dev.c:6079 [inline]
  __netif_receive_skb+0x143/0x380 net/core/dev.c:6192
  process_backlog+0x31e/0x900 net/core/dev.c:6544
  __napi_poll+0xb6/0x540 net/core/dev.c:7594
  napi_poll net/core/dev.c:7657 [inline]
  net_rx_action+0x5f7/0xda0 net/core/dev.c:7784
  handle_softirqs+0x22f/0x710 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302
  mptcp_pm_send_ack net/mptcp/pm.c:210 [inline]
 mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1
  mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002
  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762
  process_one_work kernel/workqueue.c:3263 [inline]
  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 44:
  kasan_save_stack mm/kasan/common.c:56 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
  poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
  __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
  kasan_kmalloc include/linux/kasan.h:262 [inline]
  __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748
  kmalloc_noprof include/linux/slab.h:957 [inline]
  mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385
  mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355
  mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline]
  __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529
  mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008
  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762
  process_one_work kernel/workqueue.c:3263 [inline]
  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 6630:
  kasan_save_stack mm/kasan/common.c:56 [inline]
  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
  __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
  kasan_save_free_info mm/kasan/kasan.h:406 [inline]
  poison_slab_object mm/kasan/common.c:252 [inline]
  __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
  kasan_slab_free include/linux/kasan.h:234 [inline]
  slab_free_hook mm/slub.c:2523 [inline]
  slab_free mm/slub.c:6611 [inline]
  kfree+0x197/0x950 mm/slub.c:6818
  mptcp_remove_anno_list_by_saddr+0x2d/0x40 net/mptcp/pm.c:158
  mptcp_pm_flush_addrs_and_subflows net/mptcp/pm_kernel.c:1209 [inline]
  mptcp_nl_flush_addrs_list net/mptcp/pm_kernel.c:1240 [inline]
  mptcp_pm_nl_flush_addrs_doit+0x593/0xbb0 net/mptcp/pm_kernel.c:1281
  genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
  genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
  genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
  netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552
  genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
  netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
  netlink_unicast+0x846/0xa10 net/netlink/af_netlink.c:1346
  netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
  sock_sendmsg_nosec net/socket.c:727 [inline]
  __sock_sendmsg+0x21c/0x270 net/socket.c:742
  ____sys_sendmsg+0x508/0x820 net/socket.c:2630
  ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684
  __sys_sendmsg net/socket.c:2716 [inline]
  __do_sys_sendmsg net/socket.c:2721 [inline]
  __se_sys_sendmsg net/socket.c:2719 [inline]
  __x64_sys_sendmsg+0x1a1/0x260 net/socket.c:2719
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Cc: stable@vger.kernel.org
Fixes: 00cfd77b90 ("mptcp: retransmit ADD_ADDR when timeout")
Reported-by: syzbot+2a6fbf0f0530375968df@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/691ad3c3.a70a0220.f6df1.0004.GAE@google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Geliang Tang <geliang@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251117100745.1913963-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-18 18:33:01 -08:00
Eric Dumazet
035bca3f01 mptcp: fix race condition in mptcp_schedule_work()
syzbot reported use-after-free in mptcp_schedule_work() [1]

Issue here is that mptcp_schedule_work() schedules a work,
then gets a refcount on sk->sk_refcnt if the work was scheduled.
This refcount will be released by mptcp_worker().

[A] if (schedule_work(...)) {
[B]     sock_hold(sk);
        return true;
    }

Problem is that mptcp_worker() can run immediately and complete before [B]

We need instead :

    sock_hold(sk);
    if (schedule_work(...))
        return true;
    sock_put(sk);

[1]
refcount_t: addition on 0; use-after-free.
 WARNING: CPU: 1 PID: 29 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:-1 [inline]
  __refcount_inc include/linux/refcount.h:366 [inline]
  refcount_inc include/linux/refcount.h:383 [inline]
  sock_hold include/net/sock.h:816 [inline]
  mptcp_schedule_work+0x164/0x1a0 net/mptcp/protocol.c:943
  mptcp_tout_timer+0x21/0xa0 net/mptcp/protocol.c:2316
  call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
  expire_timers kernel/time/timer.c:1798 [inline]
  __run_timers kernel/time/timer.c:2372 [inline]
  __run_timer_base+0x648/0x970 kernel/time/timer.c:2384
  run_timer_base kernel/time/timer.c:2393 [inline]
  run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
  handle_softirqs+0x22f/0x710 kernel/softirq.c:622
  __do_softirq kernel/softirq.c:656 [inline]
  run_ktimerd+0xcf/0x190 kernel/softirq.c:1138
  smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
  kthread+0x711/0x8a0 kernel/kthread.c:463
  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Cc: stable@vger.kernel.org
Fixes: 3b1d6210a9 ("mptcp: implement and use MPTCP-level retransmission")
Reported-by: syzbot+355158e7e301548a1424@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/netdev/6915b46f.050a0220.3565dc.0028.GAE@google.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251113103924.3737425-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-14 18:12:35 -08:00
Jiayuan Chen
c77b3b79a9 mptcp: Fix proto fallback detection with BPF
The sockmap feature allows bpf syscall from userspace, or based
on bpf sockops, replacing the sk_prot of sockets during protocol stack
processing with sockmap's custom read/write interfaces.
'''
tcp_rcv_state_process()
  syn_recv_sock()/subflow_syn_recv_sock()
    tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)
      bpf_skops_established       <== sockops
        bpf_sock_map_update(sk)   <== call bpf helper
          tcp_bpf_update_proto()  <== update sk_prot
'''

When the server has MPTCP enabled but the client sends a TCP SYN
without MPTCP, subflow_syn_recv_sock() performs a fallback on the
subflow, replacing the subflow sk's sk_prot with the native sk_prot.
'''
subflow_syn_recv_sock()
  subflow_ulp_fallback()
    subflow_drop_ctx()
      mptcp_subflow_ops_undo_override()
'''

Then, this subflow can be normally used by sockmap, which replaces the
native sk_prot with sockmap's custom sk_prot. The issue occurs when the
user executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops().
Here, it uses sk->sk_prot to compare with the native sk_prot, but this
is incorrect when sockmap is used, as we may incorrectly set
sk->sk_socket->ops.

This fix uses the more generic sk_family for the comparison instead.

Additionally, this also prevents a WARNING from occurring:

result from ./scripts/decode_stacktrace.sh:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \
(net/mptcp/protocol.c:4005)
Modules linked in:
...

PKRU: 55555554
Call Trace:
<TASK>
do_accept (net/socket.c:1989)
__sys_accept4 (net/socket.c:2028 net/socket.c:2057)
__x64_sys_accept (net/socket.c:2067)
x64_sys_call (arch/x86/entry/syscall_64.c:41)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
RIP: 0033:0x7f87ac92b83d

---[ end trace 0000000000000000 ]---

Fixes: 0b4f33def7 ("mptcp: fix tcp fallback crash")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20251111060307.194196-3-jiayuan.chen@linux.dev
2025-11-13 13:11:15 -08:00
Jiayuan Chen
fbade4bd08 mptcp: Disallow MPTCP subflows from sockmap
The sockmap feature allows bpf syscall from userspace, or based on bpf
sockops, replacing the sk_prot of sockets during protocol stack processing
with sockmap's custom read/write interfaces.
'''
tcp_rcv_state_process()
  subflow_syn_recv_sock()
    tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)
      bpf_skops_established       <== sockops
        bpf_sock_map_update(sk)   <== call bpf helper
          tcp_bpf_update_proto()  <== update sk_prot
'''
Consider two scenarios:

1. When the server has MPTCP enabled and the client also requests MPTCP,
   the sk passed to the BPF program is a subflow sk. Since subflows only
   handle partial data, replacing their sk_prot is meaningless and will
   cause traffic disruption.

2. When the server has MPTCP enabled but the client sends a TCP SYN
   without MPTCP, subflow_syn_recv_sock() performs a fallback on the
   subflow, replacing the subflow sk's sk_prot with the native sk_prot.
   '''
   subflow_ulp_fallback()
    subflow_drop_ctx()
      mptcp_subflow_ops_undo_override()
   '''
   Subsequently, accept::mptcp_stream_accept::mptcp_fallback_tcp_ops()
   converts the subflow to plain TCP.

For the first case, we should prevent it from being combined with sockmap
by setting sk_prot->psock_update_sk_prot to NULL, which will be blocked by
sockmap's own flow.

For the second case, since subflow_syn_recv_sock() has already restored
sk_prot to native tcp_prot/tcpv6_prot, no further action is needed.

Fixes: cec37a6e41 ("mptcp: Handle MP_CAPABLE options for outgoing connections")
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://patch.msgid.link/20251111060307.194196-2-jiayuan.chen@linux.dev
2025-11-13 09:15:41 -08:00
Kees Cook
449f68f8ff net: Convert proto callbacks from sockaddr to sockaddr_unsized
Convert struct proto pre_connect(), connect(), bind(), and bind_add()
callback function prototypes from struct sockaddr to struct sockaddr_unsized.
This does not change per-implementation use of sockaddr for passing around
an arbitrarily sized sockaddr struct. Those will be addressed in future
patches.

Additionally removes the no longer referenced struct sockaddr from
include/net/inet_common.h.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-5-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:33 -08:00
Kees Cook
85cb0757d7 net: Convert proto_ops connect() callbacks to use sockaddr_unsized
Update all struct proto_ops connect() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-3-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:32 -08:00
Kees Cook
0e50474fa5 net: Convert proto_ops bind() callbacks to use sockaddr_unsized
Update all struct proto_ops bind() callback function prototypes from
"struct sockaddr *" to "struct sockaddr_unsized *" to avoid lying to the
compiler about object sizes. Calls into struct proto handlers gain casts
that will be removed in the struct proto conversion patch.

No binary changes expected.

Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20251104002617.2752303-2-kees@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 19:10:32 -08:00
Matthieu Baerts (NGI0)
e461e8a799 mptcp: pm: in kernel: only use fullmesh endp if any
Our documentation is saying that the in-kernel PM is only using fullmesh
endpoints to establish subflows to announced addresses when at least one
endpoint has a fullmesh flag. But this was not totally correct: only
fullmesh endpoints were used if at least one endpoint *from the same
address family as the received ADD_ADDR* has the fullmesh flag.

This is confusing, and it seems clearer not to have differences
depending on the address family.

So, now, when at least one MPTCP endpoint has a fullmesh flag, the local
addresses are picked from all fullmesh endpoints, which might be 0 if
there are no endpoints for the correct address family.

One selftest needs to be adapted for this behaviour change.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251101-net-next-mptcp-fm-endp-nb-bind-v1-2-b4166772d6bb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 17:15:06 -08:00
Matthieu Baerts (NGI0)
f88191c7f3 mptcp: pm: in-kernel: record fullmesh endp nb
Instead of iterating over all endpoints, under RCU read lock, just to
check if one of them as the fullmesh flag, we can keep a counter of
fullmesh endpoint, similar to what is done with the other flags.

This counter is now checked, before iterating over all endpoints.

Similar to the other counters, this new one is also exposed. A userspace
app can then know when it is being used in a fullmesh mode, with
potentially (too) many subflows.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251101-net-next-mptcp-fm-endp-nb-bind-v1-1-b4166772d6bb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-04 17:15:06 -08:00
Jakub Kicinski
1a2352ad82 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Cross-merge networking fixes after downstream PR (net-6.18-rc4).

No conflicts, adjacent changes:

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
  ded9813d17 ("net: stmmac: Consider Tx VLAN offload tag length for maxSDU")
  26ab9830be ("net: stmmac: replace has_xxxx with core_type")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-31 06:46:03 -07:00
Paolo Abeni
fe11dfa109 mptcp: zero window probe mib
Explicitly account for MPTCP-level zero windows probe, to catch
hopefully earlier issues alike the one addressed by the previous
patch.

Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Tested-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-4-38ffff5a9ec8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 17:44:28 -07:00
Paolo Abeni
a824084b98 mptcp: restore window probe
Since commit 72377ab2d6 ("mptcp: more conservative check for zero
probes") the MPTCP-level zero window probe check is always disabled, as
the TCP-level write queue always contains at least the newly allocated
skb.

Refine the relevant check tacking in account that the above condition
and that such skb can have zero length.

Fixes: 72377ab2d6 ("mptcp: more conservative check for zero probes")
Cc: stable@vger.kernel.org
Reported-by: Geliang Tang <geliang@kernel.org>
Closes: https://lore.kernel.org/d0a814c364e744ca6b836ccd5b6e9146882e8d42.camel@kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Tested-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251028-net-mptcp-send-timeout-v1-3-38ffff5a9ec8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-10-29 17:44:28 -07:00