diff mbox series

[net,1/9] mptcp: fix data re-injection from stale subflow

Message ID 20240131-upstream-net-20240131-mptcp-ci-issues-v1-1-4c1c11e571ff@kernel.org (mailing list archive)
State Accepted
Commit b6c620dc43ccb4e802894e54b651cf81495e9598
Delegated to: Netdev Maintainers
Headers show
Series mptcp: fixes for recent issues reported by CI's | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success SINGLE THREAD; Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1067 this patch: 1067
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 0 of 0 maintainers
netdev/build_clang success Errors and warnings before: 1082 this patch: 1082
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1084 this patch: 1084
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-01--15-00 (tests: 713)

Commit Message

Matthieu Baerts Jan. 31, 2024, 9:49 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

When the MPTCP PM detects that a subflow is stale, all the packet
scheduler must re-inject all the mptcp-level unacked data. To avoid
acquiring unneeded locks, it first try to check if any unacked data
is present at all in the RTX queue, but such check is currently
broken, as it uses TCP-specific helper on an MPTCP socket.

Funnily enough fuzzers and static checkers are happy, as the accessed
memory still belongs to the mptcp_sock struct, and even from a
functional perspective the recovery completed successfully, as
the short-cut test always failed.

A recent unrelated TCP change - commit d5fed5addb2b ("tcp: reorganize
tcp_sock fast path variables") - exposed the issue, as the tcp field
reorganization makes the mptcp code always skip the re-inection.

Fix the issue dropping the bogus call: we are on a slow path, the early
optimization proved once again to be evil.

Fixes: 1e1d9d6f119c ("mptcp: handle pending data on closed subflow")
Cc: stable@vger.kernel.org
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/468
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/protocol.c | 3 ---
 1 file changed, 3 deletions(-)
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3ed4709a7509..028e8b473626 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2314,9 +2314,6 @@  bool __mptcp_retransmit_pending_data(struct sock *sk)
 	if (__mptcp_check_fallback(msk))
 		return false;
 
-	if (tcp_rtx_and_write_queues_empty(sk))
-		return false;
-
 	/* the closing socket has some data untransmitted and/or unacked:
 	 * some data in the mptcp rtx queue has not really xmitted yet.
 	 * keep it simple and re-inject the whole mptcp level rtx queue