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Message-ID: <20250329180541.34968-4-kuniyu@amazon.com>
Date: Sat, 29 Mar 2025 11:05:13 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>, "David S. Miller"
<davem@...emloft.net>, David Ahern <dsahern@...nel.org>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>
CC: Simon Horman <horms@...nel.org>, Kuniyuki Iwashima <kuniyu@...zon.com>,
Kuniyuki Iwashima <kuni1840@...il.com>, <netdev@...r.kernel.org>, "Willem de
Bruijn" <willemb@...gle.com>
Subject: [PATCH v4 net 3/3] selftest: net: Check wraparounds for sk->sk_rmem_alloc.
The test creates client and server sockets and sets INT_MAX to the
server's SO_RCVBUFFORCE.
Then, the client floods packets to the server until the UDP memory
usage reaches (INT_MAX + 1) >> PAGE_SHIFT.
Finally, both sockets are close()d, and the last assert makes sure
that the memory usage drops to 0.
If needed, we can extend the test later for other protocols.
Without patch 1:
# Starting 2 tests from 2 test cases.
# RUN so_rcvbuf.udp_ipv4.rmem_max ...
# so_rcvbuf.c:163:rmem_max:Expected pages (524800) <= *variant->max_pages (524288)
# rmem_max: Test terminated by assertion
# FAIL so_rcvbuf.udp_ipv4.rmem_max
not ok 1 so_rcvbuf.udp_ipv4.rmem_max
Without patch 2:
# RUN so_rcvbuf.udp_ipv4.rmem_max ...
# so_rcvbuf.c:170:rmem_max:max_pages: 524288
# so_rcvbuf.c:178:rmem_max:Expected get_prot_pages(_metadata, variant) (524288) == 0 (0)
# rmem_max: Test terminated by assertion
# FAIL so_rcvbuf.udp_ipv4.rmem_max
not ok 1 so_rcvbuf.udp_ipv4.rmem_max
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Reviewed-by: Willem de Bruijn <willemb@...gle.com>
---
v4: Wait RCU for at most 30 sec
v3: Rebase to the latest net.git
v2: Add some comments (Note with 1000 loops it didn't fail at ASSERT_LE)
---
tools/testing/selftests/net/.gitignore | 3 +-
tools/testing/selftests/net/Makefile | 2 +-
tools/testing/selftests/net/so_rcvbuf.c | 188 ++++++++++++++++++++++++
3 files changed, 191 insertions(+), 2 deletions(-)
create mode 100644 tools/testing/selftests/net/so_rcvbuf.c
diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index 679542f565a4..972fb07730d2 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -42,8 +42,9 @@ sk_so_peek_off
socket
so_incoming_cpu
so_netns_cookie
-so_txtime
so_rcv_listener
+so_rcvbuf
+so_txtime
stress_reuseport_listen
tap
tcp_fastopen_backup_key
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 6d718b478ed8..393ffa1c417b 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -87,7 +87,7 @@ TEST_GEN_PROGS += sk_bind_sendto_listen
TEST_GEN_PROGS += sk_connect_zero_addr
TEST_GEN_PROGS += sk_so_peek_off
TEST_PROGS += test_ingress_egress_chaining.sh
-TEST_GEN_PROGS += so_incoming_cpu
+TEST_GEN_PROGS += so_incoming_cpu so_rcvbuf
TEST_PROGS += sctp_vrf.sh
TEST_GEN_FILES += sctp_hello
TEST_GEN_FILES += ip_local_port_range
diff --git a/tools/testing/selftests/net/so_rcvbuf.c b/tools/testing/selftests/net/so_rcvbuf.c
new file mode 100644
index 000000000000..1a593033e47b
--- /dev/null
+++ b/tools/testing/selftests/net/so_rcvbuf.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright Amazon.com Inc. or its affiliates. */
+
+#include <limits.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+
+#include "../kselftest_harness.h"
+
+static int udp_max_pages;
+
+static int udp_parse_pages(struct __test_metadata *_metadata,
+ char *line, int *pages)
+{
+ int ret, unused;
+
+ if (strncmp(line, "UDP:", 4))
+ return -1;
+
+ ret = sscanf(line + 4, " inuse %d mem %d", &unused, pages);
+ ASSERT_EQ(2, ret);
+
+ return 0;
+}
+
+FIXTURE(so_rcvbuf)
+{
+ union {
+ struct sockaddr addr;
+ struct sockaddr_in addr4;
+ struct sockaddr_in6 addr6;
+ };
+ socklen_t addrlen;
+ int server;
+ int client;
+};
+
+FIXTURE_VARIANT(so_rcvbuf)
+{
+ int family;
+ int type;
+ int protocol;
+ int *max_pages;
+ int (*parse_pages)(struct __test_metadata *_metadata,
+ char *line, int *pages);
+};
+
+FIXTURE_VARIANT_ADD(so_rcvbuf, udp_ipv4)
+{
+ .family = AF_INET,
+ .type = SOCK_DGRAM,
+ .protocol = 0,
+ .max_pages = &udp_max_pages,
+ .parse_pages = udp_parse_pages,
+};
+
+FIXTURE_VARIANT_ADD(so_rcvbuf, udp_ipv6)
+{
+ .family = AF_INET6,
+ .type = SOCK_DGRAM,
+ .protocol = 0,
+ .max_pages = &udp_max_pages,
+ .parse_pages = udp_parse_pages,
+};
+
+static int get_page_shift(void)
+{
+ int page_size = getpagesize();
+ int page_shift = 0;
+
+ while (page_size > 1) {
+ page_size >>= 1;
+ page_shift++;
+ }
+
+ return page_shift;
+}
+
+FIXTURE_SETUP(so_rcvbuf)
+{
+ self->addr.sa_family = variant->family;
+
+ if (variant->family == AF_INET)
+ self->addrlen = sizeof(struct sockaddr_in);
+ else
+ self->addrlen = sizeof(struct sockaddr_in6);
+
+ udp_max_pages = (INT_MAX + 1L) >> get_page_shift();
+}
+
+FIXTURE_TEARDOWN(so_rcvbuf)
+{
+}
+
+static void create_socketpair(struct __test_metadata *_metadata,
+ FIXTURE_DATA(so_rcvbuf) *self,
+ const FIXTURE_VARIANT(so_rcvbuf) *variant)
+{
+ int ret;
+
+ self->server = socket(variant->family, variant->type, variant->protocol);
+ ASSERT_NE(self->server, -1);
+
+ self->client = socket(variant->family, variant->type, variant->protocol);
+ ASSERT_NE(self->client, -1);
+
+ ret = bind(self->server, &self->addr, self->addrlen);
+ ASSERT_EQ(ret, 0);
+
+ ret = getsockname(self->server, &self->addr, &self->addrlen);
+ ASSERT_EQ(ret, 0);
+
+ ret = connect(self->client, &self->addr, self->addrlen);
+ ASSERT_EQ(ret, 0);
+}
+
+static int get_prot_pages(struct __test_metadata *_metadata,
+ const FIXTURE_VARIANT(so_rcvbuf) *variant)
+{
+ char *line = NULL;
+ size_t unused;
+ int pages = 0;
+ FILE *f;
+
+ f = fopen("/proc/net/sockstat", "r");
+ ASSERT_NE(NULL, f);
+
+ while (getline(&line, &unused, f) != -1)
+ if (!variant->parse_pages(_metadata, line, &pages))
+ break;
+
+ free(line);
+ fclose(f);
+
+ return pages;
+}
+
+TEST_F(so_rcvbuf, rmem_max)
+{
+ int ret, i, pages;
+ char buf[16] = {};
+
+ create_socketpair(_metadata, self, variant);
+
+ ret = setsockopt(self->server, SOL_SOCKET, SO_RCVBUFFORCE,
+ &(int){INT_MAX}, sizeof(int));
+ ASSERT_EQ(ret, 0);
+
+ pages = get_prot_pages(_metadata, variant);
+ ASSERT_EQ(pages, 0);
+
+ for (i = 1; ; i++) {
+ ret = send(self->client, buf, sizeof(buf), 0);
+ ASSERT_EQ(ret, sizeof(buf));
+
+ /* Make sure we don't stop at pages == (INT_MAX >> PAGE_SHIFT)
+ * in case ASSERT_LE() should fail.
+ */
+ if (i % 10000 == 0) {
+ pages = get_prot_pages(_metadata, variant);
+
+ /* sk_rmem_alloc wrapped around by >PAGE_SIZE ? */
+ ASSERT_LE(pages, *variant->max_pages);
+
+ if (pages == *variant->max_pages)
+ break;
+ }
+ }
+
+ TH_LOG("max_pages: %d", pages);
+
+ close(self->client);
+ close(self->server);
+
+ /* Give RCU a chance to call udp_destruct_common() */
+ for (i = 0; i < 30; i++) {
+ sleep(1);
+
+ pages = get_prot_pages(_metadata, variant);
+ if (!pages)
+ break;
+ }
+
+ ASSERT_EQ(pages, 0);
+}
+
+TEST_HARNESS_MAIN
--
2.48.1
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