linux-toradex.git/net/mptcp, branch master

mptcp: fix bad accounting in __mptcp_subflow_push_pending()

2026-09-17T15:14:33+00:00

If __subflow_push_pending() errors out we should avoid updating the
copied byte counters, to avoid mismatch push call later on.

Fixes: 0fa1b3783a17 ("mptcp: use get_send wrapper")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-3-0cf5c72667c8@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: close race between scheduler and state change

2026-09-17T15:14:33+00:00

The mptcp scheduler may race with subflow sockets state change: data
transmission on the selected socket may fail and a later release could
try to use mss_now reset to 0 for a divide operation.

Address the issue by explicitly checking for the critical scenario.

Fixes: c886d70286bf ("mptcp: do not queue data on closed subflows")
Cc: stable@vger.kernel.org
Reported-by: Shardul Bankar 
Reported-by: Xinyang Ge 
Closes: https://lore.kernel.org/20260525194828.1137119-1-shardul.b@mpiricsoftware.com
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-2-0cf5c72667c8@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: avoid unneeded actions on subflow reset

2026-09-17T15:14:33+00:00

Once in a blue moon, the mptcp receive path can recursively call
mptcp_data_ready() via state change under unlucky error conditions, and
then try to hold the data lock again.

Break the recursion loop explicitly checking for the exceptional
condition.

Add a new flag instead of using an existing one like 'closing', to exit
early in subflow_state_change(), and explicitly flush the RX queue at
reset time.

This avoids unneeded processing to check for available data -- calling
get_mapping_status() and more on a dying subflow -- but also in error
reporting and worker scheduling.

Note that we must consume the currently peeked skb before invoking
mptcp_dss_corruption to avoid consuming it again after the eventual
reset has freed it.

Fixes: e32d262c89e2 ("mptcp: handle consistently DSS corruption")
Cc: stable@vger.kernel.org
Reported-by: Xinyang Ge 
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260917-net-mptcp-misc-fixes-7-3-rc4-v2-1-0cf5c72667c8@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: return sk_wait_data() errors from recvmsg()

2026-09-17T00:28:06+00:00

Commit 581302298524 ("mptcp: error out earlier on disconnect") made
mptcp_recvmsg() stop when sk_wait_data() returns an error.  The error is
stored in err, but the function then jumps to a path which returns
copied.  When no data was copied, recvmsg() therefore returns zero and
reports a false EOF.

Store the result in copied, which is the value returned by the function.
This also keeps the usual partial-read result when data was copied before
the error.

A recvmsg() blocked in one thread reproduces the issue when another
thread disconnects the same MPTCP socket with connect(AF_UNSPEC).
Before this change recvmsg() returns zero; afterwards it returns -EPIPE.

Fixes: 581302298524 ("mptcp: error out earlier on disconnect")
Cc: stable@vger.kernel.org
Signed-off-by: Mark Amirkan 
Reviewed-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260913-b4-send-mptcp-recv-error-v1-1-4eaa3684a8b8@gmail.com
Signed-off-by: Jakub Kicinski

mptcp: avoid pruning for OoW data

2026-09-09T20:32:56+00:00

Pruning is expansive and destructive, do it only when we expect
to accept the skb triggering the cleanup.

Fixes: e468d371180d ("mptcp: implemented OoO queue pruning")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-15-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: being below memory limit is a likely() condition

2026-09-09T20:32:56+00:00

The current compiler hint annotation is wrong, due to inverted
logic in the previous revision of the relevant code.

Fixes: e468d371180d ("mptcp: implemented OoO queue pruning")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-14-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: options: fix uninit-value in mptcp_write_data_fin

2026-09-09T20:32:56+00:00

When sending a DATA_FIN without data, and because the DATA_FIN occupies
1 octet of the connection-level sequence space [1], it is then required
to add a DSS mapping with specific values.

If the checksum has been negotiated, it also needs to be computed, and
included in the outgoing packet, and thus the initial csum data needs to
be reset to 0 as well. This is no longer the case since commit
cfcceb7a39fc ("tcp: shrink per-packet memset in __tcp_transmit_skb()"),
because the whole ext_copy structure is no longer zeroed by default.

This seems to be the only case where use_map is changed and set
afterwards, so initialising the csum field only in this case, along with
other fields for this specific case.

Fixes: cfcceb7a39fc ("tcp: shrink per-packet memset in __tcp_transmit_skb()")
Cc: stable@vger.kernel.org
Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.3.3 [1]
Link: https://sashiko.dev/#/patchset/20260812-net-next-mptcp-misc-feat-7-3-v1-0-1905a818f6cb%40kernel.org?part=2
Reviewed-by: Geliang Tang 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-13-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: remove unneeded READ_ONCE() annotation

2026-09-09T20:32:55+00:00

The subflow->fully_established flag is always written under the subflow
socket lock. Reading such value under the same lock does not require any
ONCE annotation.

Fixes: 581c8cbfa934 ("mptcp: annotate data-races around subflow->fully_established")
Signed-off-by: Paolo Abeni 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-10-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: pm: reset retrans_time when ADD_ADDR entry is reused

2026-09-09T20:32:55+00:00

When an ADD_ADDR entry is reused, the timer is re-armed, because the
goal is to re-announce an ADD_ADDR, and eventually retransmit it if
needed.

In this case, the retransmission counter should be reset as well, so the
re-announced address gets its retransmissions back instead of relying on
what was left before, and possibly not being able to retransmit it.

Fixes: 304ab97f4c7c ("mptcp: allow ADD_ADDR reissuance by userspace PMs")
Cc: stable@vger.kernel.org
Link: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260803-net-mptcp-misc-fixes-7-2-rc6-v2-0-b8f496d71664%40kernel.org?part=4
Reviewed-by: Mat Martineau 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-9-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski

mptcp: pm: userspace: fix address ID overflow

2026-09-09T20:32:55+00:00

When all MPTCP address IDs (1-255) are exhausted in the userspace PM,
find_next_zero_bit() returns MPTCP_PM_MAX_ADDR_ID + 1 (256). This value
overflows when stored in the u8 field e->addr.id, resulting in ID 0
being stored and the entry being incorrectly added to the list.

ID 0 is reserved for the initial connection in MPTCP, so this overflow
can cause address conflicts.

Note: the in-kernel PM already has an 'endpoints == MPTCP_PM_MAX_ADDR_ID'
check in mptcp_pm_nl_append_new_local_addr() that returns -ERANGE before
reaching find_next_zero_bit(), preventing this overflow. So this fix only
addresses the userspace PM path.

Check the find_next_zero_bit() result against MPTCP_PM_MAX_ADDR_ID and
return -ENOSPC if all IDs are truly exhausted. Move the ID allocation
check before the memory allocation so that the error path does not need
to free the allocated entry.

Fixes: 4638de5aefe5 ("mptcp: handle local addrs announced by userspace PMs")
Cc: stable@vger.kernel.org
Signed-off-by: Qing Luo 
Reviewed-by: Matthieu Baerts (NGI0) 
Signed-off-by: Matthieu Baerts (NGI0) 
Link: https://patch.msgid.link/20260908-net-mptcp-misc-fixes-7-3-rc1-v2-8-df1de70348b6@kernel.org
Signed-off-by: Jakub Kicinski