From: Florian Westphal <[email protected]>
Christoph Paasch reported following crash:
dst_release underflow
WARNING: CPU: 0 PID: 1319 at net/core/dst.c:175 dst_release+0xc1/0xd0
net/core/dst.c:175
CPU: 0 PID: 1319 Comm: syz-executor217 Not tainted
5.11.0-rc6af8e85128b4d0d24083c5cac646e891227052e0c #70
Call Trace:
rt_cache_route+0x12e/0x140 net/ipv4/route.c:1503
rt_set_nexthop.constprop.0+0x1fc/0x590 net/ipv4/route.c:1612
__mkroute_output net/ipv4/route.c:2484 [inline]
...
The worker leaves msk->subflow alone even when it
happened to close the subflow ssk associated with it.
Fixes: 866f26f2a9c33b ("mptcp: always graft subflow socket to parent")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/157
Reported-by: Christoph Paasch <[email protected]>
Suggested-by: Paolo Abeni <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
---
net/mptcp/protocol.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index aa59101ffe54..a58da04bed71 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2116,6 +2116,14 @@ static struct sock *mptcp_subflow_get_retrans(const
struct mptcp_sock *msk)
return backup;
}
+static void mptcp_dispose_initial_subflow(struct mptcp_sock *msk)
+{
+ if (msk->subflow) {
+ iput(SOCK_INODE(msk->subflow));
+ msk->subflow = NULL;
+ }
+}
+
/* subflow sockets can be either outgoing (connect) or incoming
* (accept).
*
@@ -2160,6 +2168,9 @@ static void __mptcp_close_ssk(struct sock *sk, struct
sock *ssk,
if (ssk == msk->last_snd)
msk->last_snd = NULL;
+
+ if (msk->subflow && ssk == msk->subflow->sk)
+ mptcp_dispose_initial_subflow(msk);
}
void mptcp_close_ssk(struct sock *sk, struct sock *ssk,
@@ -2529,12 +2540,6 @@ static void __mptcp_destroy_sock(struct sock *sk)
might_sleep();
- /* dispose the ancillatory tcp socket, if any */
- if (msk->subflow) {
- iput(SOCK_INODE(msk->subflow));
- msk->subflow = NULL;
- }
-
/* be sure to always acquire the join list lock, to sync vs
* mptcp_finish_join().
*/
@@ -2559,6 +2564,7 @@ static void __mptcp_destroy_sock(struct sock *sk)
sk_stream_kill_queues(sk);
xfrm_sk_free_policy(sk);
sk_refcnt_debug_release(sk);
+ mptcp_dispose_initial_subflow(msk);
sock_put(sk);
}
--
2.30.1
