selftest: Don't reuse port for SO_INCOMING_CPU test.
Jakub reported that ASSERT_EQ(cpu, i) in so_incoming_cpu.c seems to
fire somewhat randomly.
# # RUN so_incoming_cpu.before_reuseport.test3 ...
# # so_incoming_cpu.c:191:test3:Expected cpu (32) == i (0)
# # test3: Test terminated by assertion
# # FAIL so_incoming_cpu.before_reuseport.test3
# not ok 3 so_incoming_cpu.before_reuseport.test3
When the test failed, not-yet-accepted CLOSE_WAIT sockets received
SYN with a "challenging" SEQ number, which was sent from an unexpected
CPU that did not create the receiver.
The test basically does:
1. for each cpu:
1-1. create a server
1-2. set SO_INCOMING_CPU
2. for each cpu:
2-1. set cpu affinity
2-2. create some clients
2-3. let clients connect() to the server on the same cpu
2-4. close() clients
3. for each server:
3-1. accept() all child sockets
3-2. check if all children have the same SO_INCOMING_CPU with the server
The root cause was the close() in 2-4. and net.ipv4.tcp_tw_reuse.
In a loop of 2., close() changed the client state to FIN_WAIT_2, and
the peer transitioned to CLOSE_WAIT.
In another loop of 2., connect() happened to select the same port of
the FIN_WAIT_2 socket, and it was reused as the default value of
net.ipv4.tcp_tw_reuse is 2.
As a result, the new client sent SYN to the CLOSE_WAIT socket from
a different CPU, and the receiver's sk_incoming_cpu was overwritten
with unexpected CPU ID.
Also, the SYN had a different SEQ number, so the CLOSE_WAIT socket
responded with Challenge ACK. The new client properly returned RST
and effectively killed the CLOSE_WAIT socket.
This way, all clients were created successfully, but the error was
detected later by 3-2., ASSERT_EQ(cpu, i).
To avoid the failure, let's make sure that (i) the number of clients
is less than the number of available ports and (ii) such reuse never
happens.
Fixes: 6df96146b2
("selftest: Add test for SO_INCOMING_CPU.")
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Tested-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20240120031642.67014-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
parent
7267e8dcad
commit
97de5a15ed
1 changed files with 50 additions and 18 deletions
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@ -3,19 +3,16 @@
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#define _GNU_SOURCE
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#include <sched.h>
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#include <fcntl.h>
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#include <netinet/in.h>
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#include <sys/socket.h>
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#include <sys/sysinfo.h>
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#include "../kselftest_harness.h"
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#define CLIENT_PER_SERVER 32 /* More sockets, more reliable */
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#define NR_SERVER self->nproc
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#define NR_CLIENT (CLIENT_PER_SERVER * NR_SERVER)
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FIXTURE(so_incoming_cpu)
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{
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int nproc;
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int *servers;
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union {
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struct sockaddr addr;
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@ -56,12 +53,47 @@ FIXTURE_VARIANT_ADD(so_incoming_cpu, after_all_listen)
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.when_to_set = AFTER_ALL_LISTEN,
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};
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static void write_sysctl(struct __test_metadata *_metadata,
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char *filename, char *string)
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{
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int fd, len, ret;
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fd = open(filename, O_WRONLY);
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ASSERT_NE(fd, -1);
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len = strlen(string);
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ret = write(fd, string, len);
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ASSERT_EQ(ret, len);
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}
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static void setup_netns(struct __test_metadata *_metadata)
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{
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ASSERT_EQ(unshare(CLONE_NEWNET), 0);
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ASSERT_EQ(system("ip link set lo up"), 0);
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write_sysctl(_metadata, "/proc/sys/net/ipv4/ip_local_port_range", "10000 60001");
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write_sysctl(_metadata, "/proc/sys/net/ipv4/tcp_tw_reuse", "0");
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}
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#define NR_PORT (60001 - 10000 - 1)
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#define NR_CLIENT_PER_SERVER_DEFAULT 32
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static int nr_client_per_server, nr_server, nr_client;
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FIXTURE_SETUP(so_incoming_cpu)
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{
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self->nproc = get_nprocs();
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ASSERT_LE(2, self->nproc);
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setup_netns(_metadata);
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self->servers = malloc(sizeof(int) * NR_SERVER);
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nr_server = get_nprocs();
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ASSERT_LE(2, nr_server);
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if (NR_CLIENT_PER_SERVER_DEFAULT * nr_server < NR_PORT)
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nr_client_per_server = NR_CLIENT_PER_SERVER_DEFAULT;
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else
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nr_client_per_server = NR_PORT / nr_server;
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nr_client = nr_client_per_server * nr_server;
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self->servers = malloc(sizeof(int) * nr_server);
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ASSERT_NE(self->servers, NULL);
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self->in_addr.sin_family = AF_INET;
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@ -74,7 +106,7 @@ FIXTURE_TEARDOWN(so_incoming_cpu)
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{
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int i;
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for (i = 0; i < NR_SERVER; i++)
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for (i = 0; i < nr_server; i++)
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close(self->servers[i]);
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free(self->servers);
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@ -110,10 +142,10 @@ int create_server(struct __test_metadata *_metadata,
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if (variant->when_to_set == BEFORE_LISTEN)
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set_so_incoming_cpu(_metadata, fd, cpu);
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/* We don't use CLIENT_PER_SERVER here not to block
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/* We don't use nr_client_per_server here not to block
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* this test at connect() if SO_INCOMING_CPU is broken.
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*/
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ret = listen(fd, NR_CLIENT);
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ret = listen(fd, nr_client);
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ASSERT_EQ(ret, 0);
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if (variant->when_to_set == AFTER_LISTEN)
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@ -128,7 +160,7 @@ void create_servers(struct __test_metadata *_metadata,
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{
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int i, ret;
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for (i = 0; i < NR_SERVER; i++) {
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for (i = 0; i < nr_server; i++) {
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self->servers[i] = create_server(_metadata, self, variant, i);
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if (i == 0) {
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@ -138,7 +170,7 @@ void create_servers(struct __test_metadata *_metadata,
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}
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if (variant->when_to_set == AFTER_ALL_LISTEN) {
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for (i = 0; i < NR_SERVER; i++)
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for (i = 0; i < nr_server; i++)
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set_so_incoming_cpu(_metadata, self->servers[i], i);
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}
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}
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@ -149,7 +181,7 @@ void create_clients(struct __test_metadata *_metadata,
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cpu_set_t cpu_set;
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int i, j, fd, ret;
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for (i = 0; i < NR_SERVER; i++) {
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for (i = 0; i < nr_server; i++) {
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CPU_ZERO(&cpu_set);
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CPU_SET(i, &cpu_set);
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ret = sched_setaffinity(0, sizeof(cpu_set), &cpu_set);
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ASSERT_EQ(ret, 0);
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for (j = 0; j < CLIENT_PER_SERVER; j++) {
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for (j = 0; j < nr_client_per_server; j++) {
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fd = socket(AF_INET, SOCK_STREAM, 0);
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ASSERT_NE(fd, -1);
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@ -180,8 +212,8 @@ void verify_incoming_cpu(struct __test_metadata *_metadata,
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int i, j, fd, cpu, ret, total = 0;
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socklen_t len = sizeof(int);
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for (i = 0; i < NR_SERVER; i++) {
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for (j = 0; j < CLIENT_PER_SERVER; j++) {
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for (i = 0; i < nr_server; i++) {
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for (j = 0; j < nr_client_per_server; j++) {
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/* If we see -EAGAIN here, SO_INCOMING_CPU is broken */
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fd = accept(self->servers[i], &self->addr, &self->addrlen);
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ASSERT_NE(fd, -1);
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}
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}
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ASSERT_EQ(total, NR_CLIENT);
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ASSERT_EQ(total, nr_client);
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TH_LOG("SO_INCOMING_CPU is very likely to be "
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"working correctly with %d sockets.", total);
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}
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