From: Jakub Sitnicki jakub@cloudflare.com
commit 5d3919a953c3c96c02fc7a337f8376cde43ae31f upstream.
Commit 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down") introduced sleeping issues inside RCU critical sections and while holding a spinlock on sockmap/sockhash tear-down. There has to be at least one socket in the map for the problem to surface.
This adds a test that triggers the warnings for broken locking rules. Not a fix per se, but rather tooling to verify the accompanying fixes. Run on a VM with 1 vCPU to reproduce the warnings.
Fixes: 7e81a3530206 ("bpf: Sockmap, ensure sock lock held during tear down") Signed-off-by: Jakub Sitnicki jakub@cloudflare.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: John Fastabend john.fastabend@gmail.com Link: https://lore.kernel.org/bpf/20200206111652.694507-4-jakub@cloudflare.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/testing/selftests/bpf/prog_tests/sockmap_basic.c | 74 +++++++++++++++++ 1 file changed, 74 insertions(+)
--- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Cloudflare + +#include "test_progs.h" + +static int connected_socket_v4(void) +{ + struct sockaddr_in addr = { + .sin_family = AF_INET, + .sin_port = htons(80), + .sin_addr = { inet_addr("127.0.0.1") }, + }; + socklen_t len = sizeof(addr); + int s, repair, err; + + s = socket(AF_INET, SOCK_STREAM, 0); + if (CHECK_FAIL(s == -1)) + goto error; + + repair = TCP_REPAIR_ON; + err = setsockopt(s, SOL_TCP, TCP_REPAIR, &repair, sizeof(repair)); + if (CHECK_FAIL(err)) + goto error; + + err = connect(s, (struct sockaddr *)&addr, len); + if (CHECK_FAIL(err)) + goto error; + + repair = TCP_REPAIR_OFF_NO_WP; + err = setsockopt(s, SOL_TCP, TCP_REPAIR, &repair, sizeof(repair)); + if (CHECK_FAIL(err)) + goto error; + + return s; +error: + perror(__func__); + close(s); + return -1; +} + +/* Create a map, populate it with one socket, and free the map. */ +static void test_sockmap_create_update_free(enum bpf_map_type map_type) +{ + const int zero = 0; + int s, map, err; + + s = connected_socket_v4(); + if (CHECK_FAIL(s == -1)) + return; + + map = bpf_create_map(map_type, sizeof(int), sizeof(int), 1, 0); + if (CHECK_FAIL(map == -1)) { + perror("bpf_create_map"); + goto out; + } + + err = bpf_map_update_elem(map, &zero, &s, BPF_NOEXIST); + if (CHECK_FAIL(err)) { + perror("bpf_map_update"); + goto out; + } + +out: + close(map); + close(s); +} + +void test_sockmap_basic(void) +{ + if (test__start_subtest("sockmap create_update_free")) + test_sockmap_create_update_free(BPF_MAP_TYPE_SOCKMAP); + if (test__start_subtest("sockhash create_update_free")) + test_sockmap_create_update_free(BPF_MAP_TYPE_SOCKHASH); +}