From: Jakub Sitnicki <jakub@cloudflare.com>
To: bpf@vger.kernel.org
Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com,
John Fastabend <john.fastabend@gmail.com>
Subject: [PATCH bpf 3/3] selftests/bpf: Test freeing sockmap/sockhash with a socket in it
Date: Thu, 6 Feb 2020 12:16:52 +0100 [thread overview]
Message-ID: <20200206111652.694507-4-jakub@cloudflare.com> (raw)
In-Reply-To: <20200206111652.694507-1-jakub@cloudflare.com>
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>
---
.../selftests/bpf/prog_tests/sockmap_basic.c | 74 +++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
new file mode 100644
index 000000000000..07f5b462c2ef
--- /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);
+}
--
2.24.1
next prev parent reply other threads:[~2020-02-06 11:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-06 11:16 [PATCH bpf 0/3] Fix locking order and synchronization on sockmap/sockhash tear-down Jakub Sitnicki
2020-02-06 11:16 ` [PATCH bpf 1/3] bpf, sockmap: Don't sleep while holding RCU lock on tear-down Jakub Sitnicki
2020-02-06 18:59 ` John Fastabend
2020-02-06 11:16 ` [PATCH bpf 2/3] bpf, sockhash: synchronize_rcu before free'ing map Jakub Sitnicki
2020-02-06 19:01 ` John Fastabend
2020-02-06 11:16 ` Jakub Sitnicki [this message]
2020-02-06 19:03 ` [PATCH bpf 3/3] selftests/bpf: Test freeing sockmap/sockhash with a socket in it John Fastabend
2020-02-09 2:41 ` Alexei Starovoitov
2020-02-09 4:12 ` Yonghong Song
2020-02-09 15:29 ` Jakub Sitnicki
2020-02-10 3:55 ` John Fastabend
2020-02-10 11:52 ` Jakub Sitnicki
2020-02-10 23:38 ` Daniel Borkmann
2020-02-06 19:43 ` [PATCH bpf 0/3] Fix locking order and synchronization on sockmap/sockhash tear-down John Fastabend
2020-02-07 10:45 ` Jakub Sitnicki
2020-03-10 16:44 ` John Fastabend
2020-03-11 11:51 ` Jakub Sitnicki
2020-03-10 11:30 ` Jakub Sitnicki
2020-02-07 21:56 ` Daniel Borkmann
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