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mptcp: fix race in overlapping signal events

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After commit a88c9e4969 ("mptcp: do not block subflows
creation on errors"), if a signal address races with a failing
subflow creation, the subflow creation failure control path
can trigger the selection of the next address to be announced
while the current announced is still pending.

The above will cause the unintended suppression of the ADD_ADDR
announce.

Fix the issue skipping the to-be-suppressed announce before it
will mark an endpoint as already used. The relevant announce
will be triggered again when the current one will complete.

Fixes: a88c9e4969 ("mptcp: do not block subflows creation on errors")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2022-02-18 13:35:40 -08:00 committed by David S. Miller
parent 5b31dda736
commit 98247bc16a
1 changed files with 10 additions and 0 deletions
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10
net/mptcp/pm_netlink.c
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@ -546,6 +546,16 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
if (msk->pm.add_addr_signaled < add_addr_signal_max) {
local = select_signal_address(pernet, msk);
/* due to racing events on both ends we can reach here while
* previous add address is still running: if we invoke now
* mptcp_pm_announce_addr(), that will fail and the
* corresponding id will be marked as used.
* Instead let the PM machinery reschedule us when the
* current address announce will be completed.
*/
if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
return;
if (local) {
if (mptcp_pm_alloc_anno_list(msk, local)) {
__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);