From: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx> commit f448451aa62d54be16acb0034223c17e0d12bc69 upstream. This helper is confusing. It is in pm.c, but it is specific to the in-kernel PM and it cannot be used by the userspace one. Also, it simply calls one in-kernel specific function with the PM lock, while the similar mptcp_pm_remove_addr() helper requires the PM lock. What's left is the pr_debug(), which is not that useful, because a similar one is present in the only function called by this helper: mptcp_pm_nl_rm_subflow_received() After these modifications, this helper can be marked as 'static', and the lock can be taken only once in mptcp_pm_flush_addrs_and_subflows(). Note that it is not a bug fix, but it will help backporting the following commits. Fixes: 0ee4261a3681 ("mptcp: implement mptcp_pm_remove_subflow") Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx> Link: https://patch.msgid.link/20240819-net-mptcp-pm-reusing-id-v1-7-38035d40de5b@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mptcp/pm.c | 10 ---------- net/mptcp/pm_netlink.c | 16 +++++++--------- net/mptcp/protocol.h | 3 --- 3 files changed, 7 insertions(+), 22 deletions(-) --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -61,16 +61,6 @@ int mptcp_pm_remove_addr(struct mptcp_so return 0; } -int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list) -{ - pr_debug("msk=%p, rm_list_nr=%d", msk, rm_list->nr); - - spin_lock_bh(&msk->pm.lock); - mptcp_pm_nl_rm_subflow_received(msk, rm_list); - spin_unlock_bh(&msk->pm.lock); - return 0; -} - /* path manager event handlers */ void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int server_side) --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -865,8 +865,8 @@ static void mptcp_pm_nl_rm_addr_received mptcp_pm_nl_rm_addr_or_subflow(msk, &msk->pm.rm_list_rx, MPTCP_MIB_RMADDR); } -void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, - const struct mptcp_rm_list *rm_list) +static void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, + const struct mptcp_rm_list *rm_list) { mptcp_pm_nl_rm_addr_or_subflow(msk, rm_list, MPTCP_MIB_RMSUBFLOW); } @@ -1502,7 +1502,9 @@ static int mptcp_nl_remove_subflow_and_s !(entry->flags & MPTCP_PM_ADDR_FLAG_IMPLICIT)); if (remove_subflow) { - mptcp_pm_remove_subflow(msk, &list); + spin_lock_bh(&msk->pm.lock); + mptcp_pm_nl_rm_subflow_received(msk, &list); + spin_unlock_bh(&msk->pm.lock); } else if (entry->flags & MPTCP_PM_ADDR_FLAG_SUBFLOW) { /* If the subflow has been used, but now closed */ spin_lock_bh(&msk->pm.lock); @@ -1648,18 +1650,14 @@ void mptcp_pm_remove_addrs_and_subflows( alist.ids[alist.nr++] = entry->addr.id; } + spin_lock_bh(&msk->pm.lock); if (alist.nr) { - spin_lock_bh(&msk->pm.lock); msk->pm.add_addr_signaled -= alist.nr; mptcp_pm_remove_addr(msk, &alist); - spin_unlock_bh(&msk->pm.lock); } - if (slist.nr) - mptcp_pm_remove_subflow(msk, &slist); - + mptcp_pm_nl_rm_subflow_received(msk, &slist); /* Reset counters: maybe some subflows have been removed before */ - spin_lock_bh(&msk->pm.lock); bitmap_fill(msk->pm.id_avail_bitmap, MPTCP_PM_MAX_ADDR_ID + 1); msk->pm.local_addr_used = 0; spin_unlock_bh(&msk->pm.lock); --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -945,7 +945,6 @@ int mptcp_pm_announce_addr(struct mptcp_ const struct mptcp_addr_info *addr, bool echo); int mptcp_pm_remove_addr(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list); -int mptcp_pm_remove_subflow(struct mptcp_sock *msk, const struct mptcp_rm_list *rm_list); void mptcp_pm_remove_addrs(struct mptcp_sock *msk, struct list_head *rm_list); void mptcp_pm_remove_addrs_and_subflows(struct mptcp_sock *msk, struct list_head *rm_list); @@ -1047,8 +1046,6 @@ static inline u8 subflow_get_local_id(co void __init mptcp_pm_nl_init(void); void mptcp_pm_nl_work(struct mptcp_sock *msk); -void mptcp_pm_nl_rm_subflow_received(struct mptcp_sock *msk, - const struct mptcp_rm_list *rm_list); unsigned int mptcp_pm_get_add_addr_signal_max(const struct mptcp_sock *msk); unsigned int mptcp_pm_get_add_addr_accept_max(const struct mptcp_sock *msk); unsigned int mptcp_pm_get_subflows_max(const struct mptcp_sock *msk); Patches currently in stable-queue which might be from matttbe@xxxxxxxxxx are queue-6.6/mptcp-pm-avoid-possible-uaf-when-selecting-endp.patch queue-6.6/mptcp-pm-only-decrement-add_addr_accepted-for-mpj-req.patch queue-6.6/mptcp-pm-only-in-kernel-cannot-have-entries-with-id-0.patch queue-6.6/mptcp-pm-fullmesh-select-the-right-id-later.patch queue-6.6/selftests-net-lib-kill-pids-before-del-netns.patch queue-6.6/mptcp-pm-re-using-id-of-unused-flushed-subflows.patch queue-6.6/selftests-mptcp-join-validate-fullmesh-endp-on-1st-sf.patch queue-6.6/mptcp-pm-only-mark-subflow-endp-as-available.patch queue-6.6/selftests-net-lib-ignore-possible-errors.patch queue-6.6/selftests-mptcp-join-check-re-using-id-of-closed-subflow.patch queue-6.6/mptcp-pm-re-using-id-of-unused-removed-add_addr.patch queue-6.6/mptcp-pm-check-add_addr_accept_max-before-accepting-new-add_addr.patch queue-6.6/mptcp-pm-re-using-id-of-unused-removed-subflows.patch queue-6.6/mptcp-correct-mptcp_subflow_attr_ssn_offset-reserved.patch queue-6.6/mptcp-pm-remove-mptcp_pm_remove_subflow.patch