[PATCH net 0/2] mptcp: pm: Defer freeing userspace pm entries

[PATCH net 0/2] mptcp: pm: Defer freeing userspace pm entries

[Matthieu Baerts (NGI0)]

Here are two unrelated fixes for MPTCP:

- Patch 1: free userspace PM entry with RCU helpers. A fix for v6.14.

- Patch 2: avoid a warning when running diag.sh selftest. A fix for
  v6.15-rc1.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Geliang Tang (1):
      selftests: mptcp: diag: use mptcp_lib_get_info_value

Mat Martineau (1):
      mptcp: pm: Defer freeing of MPTCP userspace path manager entries

 net/mptcp/pm_userspace.c                  | 6 +++++-
 tools/testing/selftests/net/mptcp/diag.sh | 5 ++---
 2 files changed, 7 insertions(+), 4 deletions(-)
---
base-commit: 750d0ac001e85b754404178ee8ce01cbc76a03be
change-id: 20250421-net-mptcp-pm-defer-freeing-f9cd01b70043

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@kernel.org>

[PATCH net 1/2] mptcp: pm: Defer freeing of MPTCP userspace path manager entries

[Matthieu Baerts (NGI0)]

From: Mat Martineau <martineau@kernel.org>

When path manager entries are deleted from the local address list, they
are first unlinked from the address list using list_del_rcu(). The
entries must not be freed until after the RCU grace period, but the
existing code immediately frees the entry.

Use kfree_rcu_mightsleep() and adjust sk_omem_alloc in open code instead
of using the sock_kfree_s() helper. This code path is only called in a
netlink handler, so the "might sleep" function is preferable to adding
a rarely-used rcu_head member to struct mptcp_pm_addr_entry.

Fixes: 88d097316371 ("mptcp: drop free_list for deleting entries")
Cc: stable@vger.kernel.org
Signed-off-by: Mat Martineau <martineau@kernel.org>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm_userspace.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 2cb62f026b1f4420c549ab8ee6f54ffe3880d453..a715dcbe0146ed0c055d071c63257047a90a9afd 100644
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -337,7 +337,11 @@ int mptcp_pm_nl_remove_doit(struct sk_buff *skb, struct genl_info *info)
 
 	release_sock(sk);
 
-	sock_kfree_s(sk, match, sizeof(*match));
+	kfree_rcu_mightsleep(match);
+	/* Adjust sk_omem_alloc like sock_kfree_s() does, to match
+	 * with allocation of this memory by sock_kmemdup()
+	 */
+	atomic_sub(sizeof(*match), &sk->sk_omem_alloc);
 
 	err = 0;
 out:

-- 
2.48.1

Re: [PATCH net 0/2] mptcp: pm: Defer freeing userspace pm entries

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 21 Apr 2025 19:07:12 +0200 you wrote:
> Here are two unrelated fixes for MPTCP:
> 
> - Patch 1: free userspace PM entry with RCU helpers. A fix for v6.14.
> 
> - Patch 2: avoid a warning when running diag.sh selftest. A fix for
>   v6.15-rc1.
> 
> [...]

Here is the summary with links:
  - [net,1/2] mptcp: pm: Defer freeing of MPTCP userspace path manager entries
    https://git.kernel.org/netdev/net/c/13b4ece33cf9
  - [net,2/2] selftests: mptcp: diag: use mptcp_lib_get_info_value
    https://git.kernel.org/netdev/net/c/ce72fea219c1

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html