Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * This test is intended to reproduce a crash that happens when
4 * kvm_arch_hardware_disable is called and it attempts to unregister the user
5 * return notifiers.
6 */
7#include <fcntl.h>
8#include <pthread.h>
9#include <semaphore.h>
10#include <stdint.h>
11#include <stdlib.h>
12#include <unistd.h>
13#include <sys/wait.h>
14
15#include <test_util.h>
16
17#include "kvm_util.h"
18
19#define VCPU_NUM 4
20#define SLEEPING_THREAD_NUM (1 << 4)
21#define FORK_NUM (1ULL << 9)
22#define DELAY_US_MAX 2000
23
24sem_t *sem;
25
26static void guest_code(void)
27{
28 for (;;)
29 ; /* Some busy work */
30 printf("Should not be reached.\n");
31}
32
33static void *run_vcpu(void *arg)
34{
35 struct kvm_vcpu *vcpu = arg;
36 struct kvm_run *run = vcpu->run;
37
38 vcpu_run(vcpu);
39
40 TEST_ASSERT(false, "%s: exited with reason %d: %s",
41 __func__, run->exit_reason,
42 exit_reason_str(run->exit_reason));
43 pthread_exit(NULL);
44}
45
46static void *sleeping_thread(void *arg)
47{
48 int fd;
49
50 while (true) {
51 fd = open("/dev/null", O_RDWR);
52 close(fd);
53 }
54 TEST_ASSERT(false, "%s: exited", __func__);
55 pthread_exit(NULL);
56}
57
58static inline void check_create_thread(pthread_t *thread, pthread_attr_t *attr,
59 void *(*f)(void *), void *arg)
60{
61 int r;
62
63 r = pthread_create(thread, attr, f, arg);
64 TEST_ASSERT(r == 0, "%s: failed to create thread", __func__);
65}
66
67static inline void check_set_affinity(pthread_t thread, cpu_set_t *cpu_set)
68{
69 int r;
70
71 r = pthread_setaffinity_np(thread, sizeof(cpu_set_t), cpu_set);
72 TEST_ASSERT(r == 0, "%s: failed set affinity", __func__);
73}
74
75static inline void check_join(pthread_t thread, void **retval)
76{
77 int r;
78
79 r = pthread_join(thread, retval);
80 TEST_ASSERT(r == 0, "%s: failed to join thread", __func__);
81}
82
83static void run_test(uint32_t run)
84{
85 struct kvm_vcpu *vcpu;
86 struct kvm_vm *vm;
87 cpu_set_t cpu_set;
88 pthread_t threads[VCPU_NUM];
89 pthread_t throw_away;
90 void *b;
91 uint32_t i, j;
92
93 CPU_ZERO(&cpu_set);
94 for (i = 0; i < VCPU_NUM; i++)
95 CPU_SET(i, &cpu_set);
96
97 vm = vm_create(VCPU_NUM);
98
99 pr_debug("%s: [%d] start vcpus\n", __func__, run);
100 for (i = 0; i < VCPU_NUM; ++i) {
101 vcpu = vm_vcpu_add(vm, i, guest_code);
102
103 check_create_thread(&threads[i], NULL, run_vcpu, vcpu);
104 check_set_affinity(threads[i], &cpu_set);
105
106 for (j = 0; j < SLEEPING_THREAD_NUM; ++j) {
107 check_create_thread(&throw_away, NULL, sleeping_thread,
108 (void *)NULL);
109 check_set_affinity(throw_away, &cpu_set);
110 }
111 }
112 pr_debug("%s: [%d] all threads launched\n", __func__, run);
113 sem_post(sem);
114 for (i = 0; i < VCPU_NUM; ++i)
115 check_join(threads[i], &b);
116 /* Should not be reached */
117 TEST_ASSERT(false, "%s: [%d] child escaped the ninja", __func__, run);
118}
119
120void wait_for_child_setup(pid_t pid)
121{
122 /*
123 * Wait for the child to post to the semaphore, but wake up periodically
124 * to check if the child exited prematurely.
125 */
126 for (;;) {
127 const struct timespec wait_period = { .tv_sec = 1 };
128 int status;
129
130 if (!sem_timedwait(sem, &wait_period))
131 return;
132
133 /* Child is still running, keep waiting. */
134 if (pid != waitpid(pid, &status, WNOHANG))
135 continue;
136
137 /*
138 * Child is no longer running, which is not expected.
139 *
140 * If it exited with a non-zero status, we explicitly forward
141 * the child's status in case it exited with KSFT_SKIP.
142 */
143 if (WIFEXITED(status))
144 exit(WEXITSTATUS(status));
145 else
146 TEST_ASSERT(false, "Child exited unexpectedly");
147 }
148}
149
150int main(int argc, char **argv)
151{
152 uint32_t i;
153 int s, r;
154 pid_t pid;
155
156 sem = sem_open("vm_sem", O_CREAT | O_EXCL, 0644, 0);
157 sem_unlink("vm_sem");
158
159 for (i = 0; i < FORK_NUM; ++i) {
160 pid = fork();
161 TEST_ASSERT(pid >= 0, "%s: unable to fork", __func__);
162 if (pid == 0)
163 run_test(i); /* This function always exits */
164
165 pr_debug("%s: [%d] waiting semaphore\n", __func__, i);
166 wait_for_child_setup(pid);
167 r = (rand() % DELAY_US_MAX) + 1;
168 pr_debug("%s: [%d] waiting %dus\n", __func__, i, r);
169 usleep(r);
170 r = waitpid(pid, &s, WNOHANG);
171 TEST_ASSERT(r != pid,
172 "%s: [%d] child exited unexpectedly status: [%d]",
173 __func__, i, s);
174 pr_debug("%s: [%d] killing child\n", __func__, i);
175 kill(pid, SIGKILL);
176 }
177
178 sem_destroy(sem);
179 exit(0);
180}