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mptcp: fix shutdown vs fallback race

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If the MPTCP socket shutdown happens before a fallback
to TCP, and all the pending data have been already spooled,
we never close the TCP connection.

Address the issue explicitly checking for critical condition
at fallback time.

Fixes: 1e39e5a32a ("mptcp: infinite mapping sending")
Fixes: 0348c690ed ("mptcp: add the fallback check")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Paolo Abeni 2022-06-27 18:02:38 -07:00 committed by Jakub Kicinski
parent 76a13b3157
commit d51991e2e3
4 changed files with 19 additions and 6 deletions
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2
net/mptcp/options.c
View File

@ -967,7 +967,7 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
goto reset;
subflow->mp_capable = 0;
pr_fallback(msk);
__mptcp_do_fallback(msk);
mptcp_do_fallback(ssk);
return false;
}

2
net/mptcp/protocol.c
View File

@ -1245,7 +1245,7 @@ static void mptcp_update_infinite_map(struct mptcp_sock *msk,
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
pr_fallback(msk);
__mptcp_do_fallback(msk);
mptcp_do_fallback(ssk);
}
static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,

19
net/mptcp/protocol.h
View File

@ -927,12 +927,25 @@ static inline void __mptcp_do_fallback(struct mptcp_sock *msk)
set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
}
static inline void mptcp_do_fallback(struct sock *sk)
static inline void mptcp_do_fallback(struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
struct sock *sk = subflow->conn;
struct mptcp_sock *msk;
msk = mptcp_sk(sk);
__mptcp_do_fallback(msk);
if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) {
gfp_t saved_allocation = ssk->sk_allocation;
/* we are in a atomic (BH) scope, override ssk default for data
* fin allocation
*/
ssk->sk_allocation = GFP_ATOMIC;
ssk->sk_shutdown |= SEND_SHUTDOWN;
tcp_shutdown(ssk, SEND_SHUTDOWN);
ssk->sk_allocation = saved_allocation;
}
}
#define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%p)", __func__, a)

2
net/mptcp/subflow.c
View File

@ -1279,7 +1279,7 @@ static bool subflow_check_data_avail(struct sock *ssk)
return false;
}
__mptcp_do_fallback(msk);
mptcp_do_fallback(ssk);
}
skb = skb_peek(&ssk->sk_receive_queue);