netdev - [PATCH net 2/4] mptcp: properly annotate nested lock

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Date:   Wed, 16 Dec 2020 12:48:33 +0100
From:   Paolo Abeni <pabeni@...hat.com>
To:     netdev@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, mptcp@...ts.01.org
Subject: [PATCH net 2/4] mptcp: properly annotate nested lock

MPTCP closes the subflows while holding the msk-level lock.
While acquiring the subflow socket lock we need to use the
correct nested annotation, or we can hit a lockdep splat
at runtime.

Reported-and-tested-by: Geliang Tang <geliangtang@...il.com>
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
 net/mptcp/protocol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d24243a28fce..64c0c54c80e8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2119,7 +2119,7 @@ void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 
 	list_del(&subflow->node);
 
-	lock_sock(ssk);
+	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
 
 	/* if we are invoked by the msk cleanup code, the subflow is
 	 * already orphaned
-- 
2.26.2