From: Florian Westphal <fw@xxxxxxxxx>
[ Upstream commit 17aee05dc8822e354f5ad2d68ee39e3ba4b6acf2 ]
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 <cpaasch@xxxxxxxxx>
Suggested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Acked-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 64b8a49652ae..7345df40385a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2100,6 +2100,14 @@ 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).
*
@@ -2144,6 +2152,9 @@ 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);
}
static unsigned int mptcp_sync_mss(struct sock *sk, u32 pmtu)
@@ -2533,12 +2544,6 @@ 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().
*/
@@ -2563,6 +2568,7 @@ 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
