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2026-02-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netPaolo Abeni
Merge in late fixes in preparation for the net-next PR. Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-02-10mptcp: allow overridden write_space to be invokedGeliang Tang
Future extensions with psock will override their own sk->sk_write_space callback. This patch ensures that the overridden sk_write_space can be invoked by MPTCP. INDIRECT_CALL is used to keep the default path optimised. Note that sk->sk_write_space was never called directly with MPTCP sockets, so changing it to sk_stream_write_space in the init, and using it from mptcp_write_space() is not supposed to change the current behaviour. This patch is shared early to ease discussions around future RFC and avoid confusions with this "fix" that is needed for different future extensions. Suggested-by: Paolo Abeni <pabeni@redhat.com> Co-developed-by: Gang Yan <yangang@kylinos.cn> Signed-off-by: Gang Yan <yangang@kylinos.cn> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260206-net-next-mptcp-write_space-override-v2-1-e0b12be818c6@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-06mptcp: fix kdoc warningsMatthieu Baerts (NGI0)
The following warnings were visible: $ ./scripts/kernel-doc -Wall -none \ net/mptcp/ include/net/mptcp.h include/uapi/linux/mptcp*.h \ include/trace/events/mptcp.h Warning: net/mptcp/token.c:108 No description found for return value of 'mptcp_token_new_request' Warning: net/mptcp/token.c:151 No description found for return value of 'mptcp_token_new_connect' Warning: net/mptcp/token.c:246 No description found for return value of 'mptcp_token_get_sock' Warning: net/mptcp/token.c:298 No description found for return value of 'mptcp_token_iter_next' Warning: net/mptcp/protocol.c:4431 No description found for return value of 'mptcp_splice_read' Warning: include/uapi/linux/mptcp_pm.h:13 missing initial short description on line: * enum mptcp_event_type Address all of them: either by using the 'Return:' keyword, or by adding a missing initial short description. The MPTCP CI will soon report issues with kdoc to avoid introducing new issues and being flagged by the Netdev CI. Reviewed-by: Geliang Tang <geliang@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260205-net-mptcp-misc-fixes-6-19-rc8-v2-3-c2720ce75c34@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-06mptcp: pm: in-kernel: clarify mptcp_pm_remove_anno_addr()Matthieu Baerts (NGI0)
The variable 'ret' was used, but it was not cleared what it was, and probably led to an issue [1]. Rename it to 'announced' to avoid confusions. While at it, remove the returned value of the helper: it is only used in one place, and the returned value is not used. Link: https://github.com/multipath-tcp/mptcp_net-next/issues/606 [1] Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260205-net-mptcp-misc-fixes-6-19-rc8-v2-2-c2720ce75c34@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-06mptcp: pm: in-kernel: always set ID as avail when rm endpMatthieu Baerts (NGI0)
Syzkaller managed to find a combination of actions that was generating this warning: WARNING: net/mptcp/pm_kernel.c:1074 at __mark_subflow_endp_available net/mptcp/pm_kernel.c:1074 [inline], CPU#1: syz.7.48/2535 WARNING: net/mptcp/pm_kernel.c:1074 at mptcp_pm_nl_fullmesh net/mptcp/pm_kernel.c:1446 [inline], CPU#1: syz.7.48/2535 WARNING: net/mptcp/pm_kernel.c:1074 at mptcp_pm_nl_set_flags_all net/mptcp/pm_kernel.c:1474 [inline], CPU#1: syz.7.48/2535 WARNING: net/mptcp/pm_kernel.c:1074 at mptcp_pm_nl_set_flags+0x5de/0x640 net/mptcp/pm_kernel.c:1538, CPU#1: syz.7.48/2535 Modules linked in: CPU: 1 UID: 0 PID: 2535 Comm: syz.7.48 Not tainted 6.18.0-03987-gea5f5e676cf5 #17 PREEMPT(voluntary) Hardware name: QEMU Ubuntu 25.10 PC (i440FX + PIIX, 1996), BIOS 1.17.0-debian-1.17.0-1 04/01/2014 RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:1074 [inline] RIP: 0010:mptcp_pm_nl_fullmesh net/mptcp/pm_kernel.c:1446 [inline] RIP: 0010:mptcp_pm_nl_set_flags_all net/mptcp/pm_kernel.c:1474 [inline] RIP: 0010:mptcp_pm_nl_set_flags+0x5de/0x640 net/mptcp/pm_kernel.c:1538 Code: 89 c7 e8 c5 8c 73 fe e9 f7 fd ff ff 49 83 ef 80 e8 b7 8c 73 fe 4c 89 ff be 03 00 00 00 e8 4a 29 e3 fe eb ac e8 a3 8c 73 fe 90 <0f> 0b 90 e9 3d ff ff ff e8 95 8c 73 fe b8 a1 ff ff ff eb 1a e8 89 RSP: 0018:ffffc9001535b820 EFLAGS: 00010287 netdevsim0: tun_chr_ioctl cmd 1074025677 RAX: ffffffff82da294d RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc900096d0000 RSI: 00000000000006d6 RDI: 00000000000006d7 netdevsim0: linktype set to 823 RBP: ffff88802cdb2240 R08: 00000000000104ae R09: ffffffffffffffff R10: ffffffff82da27d4 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88801246d8c0 R14: ffffc9001535b8b8 R15: ffff88802cdb1800 FS: 00007fc6ac5a76c0(0000) GS:ffff8880f90c8000(0000) knlGS:0000000000000000 netlink: 'syz.3.50': attribute type 5 has an invalid length. CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 netlink: 1232 bytes leftover after parsing attributes in process `syz.3.50'. CR2: 0000200000010000 CR3: 0000000025b1a000 CR4: 0000000000350ef0 Call Trace: <TASK> mptcp_pm_set_flags net/mptcp/pm_netlink.c:277 [inline] mptcp_pm_nl_set_flags_doit+0x1d7/0x210 net/mptcp/pm_netlink.c:282 genl_family_rcv_msg_doit+0x117/0x180 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x3a8/0x3f0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x16d/0x240 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x3e9/0x4c0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x4ab/0x5b0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0xc9/0xf0 net/socket.c:733 ____sys_sendmsg+0x272/0x3b0 net/socket.c:2608 ___sys_sendmsg+0x2de/0x320 net/socket.c:2662 __sys_sendmsg net/socket.c:2694 [inline] __do_sys_sendmsg net/socket.c:2699 [inline] __se_sys_sendmsg net/socket.c:2697 [inline] __x64_sys_sendmsg+0x110/0x1a0 net/socket.c:2697 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xed/0x360 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc6adb66f6d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fc6ac5a6ff8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fc6addf5fa0 RCX: 00007fc6adb66f6d RDX: 0000000000048084 RSI: 00002000000002c0 RDI: 000000000000000e RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 netlink: 'syz.5.51': attribute type 2 has an invalid length. R13: 00007fff25e91fe0 R14: 00007fc6ac5a7ce4 R15: 00007fff25e920d7 </TASK> The actions that caused that seem to be: - Create an MPTCP endpoint for address A without any flags - Create a new MPTCP connection from address A - Remove the MPTCP endpoint: the corresponding subflows will be removed - Recreate the endpoint with the same ID, but with the subflow flag - Change the same endpoint to add the fullmesh flag In this case, msk->pm.local_addr_used has been kept to 0 as expected, but the corresponding bit in msk->pm.id_avail_bitmap was still unset after having removed the endpoint, causing the splat later on. When removing an endpoint, the corresponding endpoint ID was only marked as available for "signal" types with an announced address, plus all "subflow" types, but not the other types like an endpoint corresponding to the initial subflow. In these cases, re-creating an endpoint with the same ID didn't signal/create anything. Here, adding the fullmesh flag was creating the splat when calling __mark_subflow_endp_available() from mptcp_pm_nl_fullmesh(), because msk->pm.local_addr_used was set to 0 while the ID was marked as used. To fix this issue, the corresponding bit in msk->pm.id_avail_bitmap can always be set as available when removing an MPTCP in-kernel endpoint. In other words, moving the call to __set_bit() to do it in all cases, except for "subflow" types where this bit is handled in a dedicated helper. Note: instead of adding a new spin_(un)lock_bh that would be taken in all cases, do all the actions requiring the spin lock under the same block. This modification potentially fixes another issue reported by syzbot, see [1]. But without a reproducer or more details about what exactly happened before, it is hard to confirm. Fixes: e255683c06df ("mptcp: pm: re-using ID of unused removed ADD_ADDR") Cc: stable@vger.kernel.org Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/606 Reported-by: syzbot+f56f7d56e2c6e11a01b6@syzkaller.appspotmail.com Closes: https://lore.kernel.org/68fcfc4a.050a0220.346f24.02fb.GAE@google.com [1] Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260205-net-mptcp-misc-fixes-6-19-rc8-v2-1-c2720ce75c34@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04mptcp: Change some dubious min_t(int, ...) to min()David Laight
There are two: min_t(int, xxx, mptcp_wnd_end(msk) - msk->snd_nxt); Both mptcp_wnd_end(msk) and msk->snd_nxt are u64, their difference (aka the window size) might be limited to 32 bits - but that isn't knowable from this code. So checks being added to min_t() detect the potential discard of significant bits. Provided the 'avail_size' and return of mptcp_check_allowed_size() are changed to an unsigned type (size_t matches the type the caller uses) both min_t() can be changed to min(). Signed-off-by: David Laight <david.laight.linux@gmail.com> Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> [ wrapped too long lines when declaring mptcp_check_allowed_size() ] Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-6-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04mptcp: pm: align endpoint flags size with the NL specsMatthieu Baerts (NGI0)
The MPTCP Netlink specs describe the 'flags' as a u32 type. Internally, a u8 type was used. Using a u8 is currently fine, because only the 5 first bits are used. But there is also no reason not to be aligns with the specs, and to stick to a u8. Especially because there is a whole of 3 bytes after in both mptcp_pm_local and mptcp_pm_addr_entry structures. Also, setting it to a u32 will allow future flags, just in case. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-5-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04trace: mptcp: add mptcp_rcvbuf_grow tracepointPaolo Abeni
Similar to tcp, provide a new tracepoint to better understand mptcp_rcv_space_adjust() behavior, which presents many artifacts. Note that the used format string is so long that I preferred wrap it, contrary to guidance for quoted strings. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-4-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04mptcp: consolidate rcv space initPaolo Abeni
MPTCP uses several calls of the mptcp_rcv_space_init() helper to initialize the receive space, with a catch-up call in mptcp_rcv_space_adjust(). Drop all the other strictly not needed invocations and move constant fields initialization at socket init/reset time. This removes a bit of complexity from mptcp DRS code. No functional changes intended. Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-3-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04mptcp: fix receive space timestamp initializationPaolo Abeni
MPTCP initialize the receive buffer stamp in mptcp_rcv_space_init(), using the provided subflow stamp. Such helper is invoked in several places; for passive sockets, space init happened at clone time. In such scenario, MPTCP ends-up accesses the subflow stamp before its initialization, leading to quite randomic timing for the first receive buffer auto-tune event, as the timestamp for newly created subflow is not refreshed there. Fix the issue moving the stamp initialization out of the mentioned helper, at the data transfer start, and always using a fresh timestamp. Fixes: 013e3179dbd2 ("mptcp: fix rcv space initialization") Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260203-net-next-mptcp-misc-feat-6-20-v1-2-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-04mptcp: do not account for OoO in mptcp_rcvbuf_grow()Paolo Abeni
MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2]. Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated. This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops. Fixes: e118cdc34dd1 ("mptcp: rcvbuf auto-tuning improvement") 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/20260203-net-next-mptcp-misc-feat-6-20-v1-1-31ec8bfc56d1@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-02mptcp: implement .splice_readGeliang Tang
This patch implements .splice_read interface of mptcp struct proto_ops as mptcp_splice_read() with reference to tcp_splice_read(). Corresponding to __tcp_splice_read(), __mptcp_splice_read() is defined, invoking mptcp_read_sock() instead of tcp_read_sock(). mptcp_splice_read() is almost the same as tcp_splice_read(), except for sock_rps_record_flow(). Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260130-net-next-mptcp-splice-v2-4-31332ba70d7f@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-02mptcp: implement .read_sockGeliang Tang
Current in-kernel TCP sockets -- i.e. from nvme_tcp_try_recv() -- need to call .read_sock interface of struct proto_ops, but it's not implemented in MPTCP. This patch implements it with reference to __tcp_read_sock() and __mptcp_recvmsg_mskq(). Corresponding to tcp_recv_skb(), a new helper for MPTCP named mptcp_recv_skb() is added to peek a skb from sk->sk_receive_queue. Compared with __mptcp_recvmsg_mskq(), mptcp_read_sock() uses sk->sk_rcvbuf as the max read length. The LISTEN status is checked before the while loop, and mptcp_recv_skb() and mptcp_cleanup_rbuf() are invoked after the loop. In the loop, all flags checks for __mptcp_recvmsg_mskq() are removed. Reviewed-by: Hannes Reinecke <hare@kernel.org> Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Link: https://patch.msgid.link/20260130-net-next-mptcp-splice-v2-2-31332ba70d7f@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-02-02mptcp: add eat_recv_skb helperGeliang Tang
This patch extracts the free skb related code in __mptcp_recvmsg_mskq() into a new helper mptcp_eat_recv_skb(). This new helper will be used in the next patch. Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn> Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://patch.msgid.link/20260130-net-next-mptcp-splice-v2-1-31332ba70d7f@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-01-28mptcp: only reset subflow errors when propagatedMatthieu Baerts (NGI0)
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: 15cc10453398 ("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>
2026-01-28mptcp: avoid dup SUB_CLOSED events after disconnectMatthieu Baerts (NGI0)
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: d82809b6c5f2 ("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>
2026-01-26mptcp: fix race in mptcp_pm_nl_flush_addrs_doit()Eric Dumazet
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: 141694df6573 ("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>
2025-12-23mptcp: ensure context reset on disconnect()Paolo Abeni
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: ae155060247b ("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>
2025-12-23mptcp: fallback earlier on simult connectionPaolo Abeni
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: 23e89e8ee7be ("tcp: Don't drop SYN+ACK for simultaneous connect().") [1] Fixes: 4fd19a307016 ("mptcp: fix inconsistent state on fastopen race") [2] Fixes: 1e777f39b4d7 ("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>
2025-12-08mptcp: avoid deadlock on fallback while reinjectingPaolo Abeni
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: f8a1d9b18c5e ("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>
2025-12-08mptcp: schedule rtx timer only after pushing dataPaolo Abeni
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 27b0e701d387 ("mptcp: drop bogus optimization in __mptcp_check_push()") Fixes: 33d41c9cd74c ("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>
2025-12-08mptcp: pm: ignore unknown endpoint flagsMatthieu Baerts (NGI0)
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: 01cacb00b35c ("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>
2025-12-08mptcp: select CRYPTO_LIB_UTILS instead of CRYPTOEric Biggers
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>
2025-11-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Conflicts: net/xdp/xsk.c 0ebc27a4c67d ("xsk: avoid data corruption on cq descriptor number") 8da7bea7db69 ("xsk: add indirect call for xsk_destruct_skb") 30ed05adca4a ("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>
2025-11-27mptcp: Initialise rcv_mss before calling tcp_send_active_reset() in ↵Kuniyuki Iwashima
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 499350a5a6e7 ("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: ae155060247b ("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>
2025-11-26mptcp: clear scheduled subflows on retransmitPaolo Abeni
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: ee2708aedad0 ("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>
2025-11-25tcp: remove icsk->icsk_retransmit_timerEric Dumazet
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>
2025-11-25tcp: introduce icsk->icsk_keepalive_timerEric Dumazet
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>
2025-11-25tcp: rename icsk_timeout() to tcp_timeout_expires()Eric Dumazet
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>
2025-11-25tools: ynl-gen: add regeneration commentAsbjørn Sloth Tønnesen
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>
2025-11-24mptcp: leverage the backlog for RX packet processingPaolo Abeni
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>
2025-11-24mptcp: introduce mptcp-level backlogPaolo Abeni
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>
2025-11-24mptcp: borrow forward memory from subflowPaolo Abeni
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>
2025-11-24mptcp: handle first subflow closing consistentlyPaolo Abeni
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>
2025-11-24mptcp: drop the __mptcp_data_ready() helperPaolo Abeni
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>
2025-11-24mptcp: make mptcp_destroy_common() staticPaolo Abeni
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>
2025-11-24mptcp: do not miss early first subflow close event notificationPaolo Abeni
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>
2025-11-24mptcp: ensure the kernel PM does not take action too latePaolo Abeni
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>
2025-11-24mptcp: cleanup fallback dummy mapping generationPaolo Abeni
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>
2025-11-24mptcp: cleanup fallback data fin receptionPaolo Abeni
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>
2025-11-24mptcp: fix memcg accounting for passive socketsPaolo Abeni
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: cf7da0d66cc1 ("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>
2025-11-24mptcp: grafting MPJ subflow earlierPaolo Abeni
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>
2025-11-24mptcp: factor-out cgroup data inherit helperPaolo Abeni
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>
2025-11-20Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.18-rc7). No conflicts, adjacent changes: tools/testing/selftests/net/af_unix/Makefile e1bb28bf13f4 ("selftest: af_unix: Add test for SO_PEEK_OFF.") 45a1cd8346ca ("selftests: af_unix: Add tests for ECONNRESET and EOF semantics") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-11-20Merge tag 'net-6.18-rc7' of ↵Linus Torvalds
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 ...
2025-11-19mptcp: fix address removal logic in mptcp_pm_nl_rm_addrGang Yan
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: 636113918508 ("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>
2025-11-19mptcp: fix duplicate reset on fastclosePaolo Abeni
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: d21f83485518 ("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>
2025-11-19mptcp: decouple mptcp fastclose from tcp closePaolo Abeni
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: d21f83485518 ("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>
2025-11-19mptcp: do not fallback when OoO is presentPaolo Abeni
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: e32d262c89e2 ("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>
2025-11-19mptcp: fix premature close in case of fallbackPaolo Abeni
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: f09b0ad55a11 ("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>
generated by cgit v1.2.3 (git 2.25.1) at 2026-08-06 23:02:29 +0000