5.15-stable review patch. If anyone has any objections, please let me know.
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From: "Matthieu Baerts (NGI0)" matttbe@kernel.org
commit 1c1f721375989579e46741f59523e39ec9b2a9bd upstream.
Adding the following warning ...
WARN_ON_ONCE(msk->pm.add_addr_accepted == 0)
... before decrementing the add_addr_accepted counter helped to find a bug when running the "remove single subflow" subtest from the mptcp_join.sh selftest.
Removing a 'subflow' endpoint will first trigger a RM_ADDR, then the subflow closure. Before this patch, and upon the reception of the RM_ADDR, the other peer will then try to decrement this add_addr_accepted. That's not correct because the attached subflows have not been created upon the reception of an ADD_ADDR.
A way to solve that is to decrement the counter only if the attached subflow was an MP_JOIN to a remote id that was not 0, and initiated by the host receiving the RM_ADDR.
Fixes: d0876b2284cf ("mptcp: add the incoming RM_ADDR support") 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/20240819-net-mptcp-pm-reusing-id-v1-9-38035d40de5b@... Signed-off-by: Jakub Kicinski kuba@kernel.org [ Conflicts in pm_netlink.c, because the context is different, but the same lines can still be modified. The conflicts are due to commit 4d25247d3ae4 ("mptcp: bypass in-kernel PM restrictions for non-kernel PMs") and commit a88c9e496937 ("mptcp: do not block subflows creation on errors"), adding new features and not present in this version. Note that because some features to better track subflows are missing in this version, it is required to remove the WARN_ON, because the counter could be 0 in some cases. ] Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mptcp/pm_netlink.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -757,7 +757,7 @@ static void mptcp_pm_nl_rm_addr_or_subfl mptcp_close_ssk(sk, ssk, subflow); spin_lock_bh(&msk->pm.lock);
- removed = true; + removed |= subflow->request_join; msk->pm.subflows--; if (rm_type == MPTCP_MIB_RMSUBFLOW) __MPTCP_INC_STATS(sock_net(sk), rm_type); @@ -767,7 +767,11 @@ static void mptcp_pm_nl_rm_addr_or_subfl if (!removed) continue;
- if (rm_type == MPTCP_MIB_RMADDR) { + if (rm_type == MPTCP_MIB_RMADDR && rm_list->ids[i] && + msk->pm.add_addr_accepted != 0) { + /* Note: if the subflow has been closed before, this + * add_addr_accepted counter will not be decremented. + */ msk->pm.add_addr_accepted--; WRITE_ONCE(msk->pm.accept_addr, true); } else if (rm_type == MPTCP_MIB_RMSUBFLOW) {