Commit b5c52908 authored by Gang Yan's avatar Gang Yan Committed by Jakub Kicinski
Browse files

mptcp: fix scheduling with atomic in timestamp sockopt 



Using lock_sock_fast() (atomic context) around sock_set_timestamp()
and sock_set_timestamping() is unsafe, as both helpers can sleep.

Replace lock_sock_fast() with sleepable lock_sock()/release_sock()
to avoid scheduling while atomic panic.

Fixes: 9061f24b ("mptcp: sockopt: propagate timestamp request to subflows")
Cc: stable@vger.kernel.org
Reported-by: default avatarSashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260420093343.16443-1-gang.yan@linux.dev


Signed-off-by: default avatarGang Yan <yangang@kylinos.cn>
Reviewed-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260427-net-mptcp-misc-fixes-7-1-rc2-v1-2-7432b7f279fa@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5f95c21f

net/mptcp/sockopt.c

+4 −4
Original line number Diff line number Diff line
@@ -159,10 +159,10 @@ static int mptcp_setsockopt_sol_socket_tstamp(struct mptcp_sock *msk, int optnam 
	lock_sock(sk);

	mptcp_for_each_subflow(msk, subflow) {

		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);

		bool slow = lock_sock_fast(ssk);



		lock_sock(ssk);

		sock_set_timestamp(ssk, optname, !!val);

		unlock_sock_fast(ssk, slow);

		release_sock(ssk);

	}



	release_sock(sk);
@@ -235,10 +235,10 @@ static int mptcp_setsockopt_sol_socket_timestamping(struct mptcp_sock *msk, 


	mptcp_for_each_subflow(msk, subflow) {

		struct sock *ssk = mptcp_subflow_tcp_sock(subflow);

		bool slow = lock_sock_fast(ssk);



		lock_sock(ssk);

		sock_set_timestamping(ssk, optname, timestamping);

		unlock_sock_fast(ssk, slow);

		release_sock(ssk);

	}



	release_sock(sk);