Commit 66418447 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'bpf-fix-recursive-lock-and-add-test' 

Jiayuan Chen says:

====================
bpf: fix recursive lock and add test

1. fix recursive lock when ebpf prog return SK_PASS.
2. add selftest to reproduce recursive lock.

Note that the test code can reproduce the 'dead-lock' and if just
the selftest merged without first patch, the test case will
definitely fail, because the issue of deadlock is inevitable.

v1: https://lore.kernel.org/55fc6114-7e64-4b65-86d2-92cfd1e9e92f@linux.dev/


====================

Acked-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20241118030910.36230-1-mrpre@163.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 21742be8 0c4d5cb9

net/core/skmsg.c

+2 −2
Original line number Diff line number Diff line
@@ -1117,9 +1117,9 @@ static void sk_psock_strp_data_ready(struct sock *sk) 
		if (tls_sw_has_ctx_rx(sk)) {

			psock->saved_data_ready(sk);

		} else {

			write_lock_bh(&sk->sk_callback_lock);

			read_lock_bh(&sk->sk_callback_lock);

			strp_data_ready(&psock->strp);

			write_unlock_bh(&sk->sk_callback_lock);

			read_unlock_bh(&sk->sk_callback_lock);

		}

	}

	rcu_read_unlock();

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

+54 −0
Original line number Diff line number Diff line
@@ -501,6 +501,58 @@ static void test_sockmap_skb_verdict_shutdown(void) 
	test_sockmap_pass_prog__destroy(skel);

}



static void test_sockmap_stream_pass(void)

{

	int zero = 0, sent, recvd;

	int verdict, parser;

	int err, map;

	int c = -1, p = -1;

	struct test_sockmap_pass_prog *pass = NULL;

	char snd[256] = "0123456789";

	char rcv[256] = "0";



	pass = test_sockmap_pass_prog__open_and_load();

	verdict = bpf_program__fd(pass->progs.prog_skb_verdict);

	parser = bpf_program__fd(pass->progs.prog_skb_parser);

	map = bpf_map__fd(pass->maps.sock_map_rx);



	err = bpf_prog_attach(parser, map, BPF_SK_SKB_STREAM_PARSER, 0);

	if (!ASSERT_OK(err, "bpf_prog_attach stream parser"))

		goto out;



	err = bpf_prog_attach(verdict, map, BPF_SK_SKB_STREAM_VERDICT, 0);

	if (!ASSERT_OK(err, "bpf_prog_attach stream verdict"))

		goto out;



	err = create_pair(AF_INET, SOCK_STREAM, &c, &p);

	if (err)

		goto out;



	/* sk_data_ready of 'p' will be replaced by strparser handler */

	err = bpf_map_update_elem(map, &zero, &p, BPF_NOEXIST);

	if (!ASSERT_OK(err, "bpf_map_update_elem(p)"))

		goto out_close;



	/*

	 * as 'prog_skb_parser' return the original skb len and

	 * 'prog_skb_verdict' return SK_PASS, the kernel will just

	 * pass it through to original socket 'p'

	 */

	sent = xsend(c, snd, sizeof(snd), 0);

	ASSERT_EQ(sent, sizeof(snd), "xsend(c)");



	recvd = recv_timeout(p, rcv, sizeof(rcv), SOCK_NONBLOCK,

			     IO_TIMEOUT_SEC);

	ASSERT_EQ(recvd, sizeof(rcv), "recv_timeout(p)");



out_close:

	close(c);

	close(p);



out:

	test_sockmap_pass_prog__destroy(pass);

}



static void test_sockmap_skb_verdict_fionread(bool pass_prog)

{

	int err, map, verdict, c0 = -1, c1 = -1, p0 = -1, p1 = -1;
@@ -923,6 +975,8 @@ void test_sockmap_basic(void) 
		test_sockmap_progs_query(BPF_SK_SKB_VERDICT);

	if (test__start_subtest("sockmap skb_verdict shutdown"))

		test_sockmap_skb_verdict_shutdown();

	if (test__start_subtest("sockmap stream parser and verdict pass"))

		test_sockmap_stream_pass();

	if (test__start_subtest("sockmap skb_verdict fionread"))

		test_sockmap_skb_verdict_fionread(true);

	if (test__start_subtest("sockmap skb_verdict fionread on drop"))