From: Alexey Dobriyan <adobriyan@xxxxxxxxx> Subject: tools/testing/selftests/proc/proc-pid-vm.c: test with vsyscall in mind : selftests: proc: proc-pid-vm : ======================================== : proc-pid-vm: proc-pid-vm.c:277: main: Assertion `rv == strlen(buf0)' failed. : Aborted Because the vsyscall mapping is enabled. Read from vsyscall page to tell if vsyscall is being used. Link: http://lkml.kernel.org/r/20190307183204.GA11405@avx2 Link: http://lkml.kernel.org/r/20190219094722.GB28258@shao2-debian Fixes: 34aab6bec23e7e9 ("proc: test /proc/*/maps, smaps, smaps_rollup, statm") Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx> Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/tools/testing/selftests/proc/proc-pid-vm.c~proc-test-with-vsyscall-in-mind +++ a/tools/testing/selftests/proc/proc-pid-vm.c @@ -29,6 +29,7 @@ #include <errno.h> #include <sched.h> #include <signal.h> +#include <stdbool.h> #include <stdint.h> #include <stdio.h> #include <string.h> @@ -36,11 +37,14 @@ #include <sys/mount.h> #include <sys/types.h> #include <sys/stat.h> +#include <sys/wait.h> #include <fcntl.h> #include <unistd.h> #include <sys/syscall.h> #include <sys/uio.h> #include <linux/kdev_t.h> +#include <sys/time.h> +#include <sys/resource.h> static inline long sys_execveat(int dirfd, const char *pathname, char **argv, char **envp, int flags) { @@ -205,12 +209,44 @@ static int make_exe(const uint8_t *paylo } #endif +static bool g_vsyscall = false; + +static const char str_vsyscall[] = +"ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0 [vsyscall]\n"; + #ifdef __x86_64__ +/* + * vsyscall page can't be unmapped, probe it with memory load. + */ +static void vsyscall(void) +{ + pid_t pid; + int wstatus; + + pid = fork(); + if (pid < 0) { + fprintf(stderr, "fork, errno %d\n", errno); + exit(1); + } + if (pid == 0) { + struct rlimit rlim = {0, 0}; + (void)setrlimit(RLIMIT_CORE, &rlim); + *(volatile int *)0xffffffffff600000UL; + exit(0); + } + wait(&wstatus); + if (WIFEXITED(wstatus)) { + g_vsyscall = true; + } +} + int main(void) { int pipefd[2]; int exec_fd; + vsyscall(); + atexit(ate); make_private_tmp(); @@ -261,9 +297,9 @@ int main(void) snprintf(buf0 + MAPS_OFFSET, sizeof(buf0) - MAPS_OFFSET, "/tmp/#%llu (deleted)\n", (unsigned long long)st.st_ino); - /* Test /proc/$PID/maps */ { + const size_t len = strlen(buf0) + (g_vsyscall ? strlen(str_vsyscall) : 0); char buf[256]; ssize_t rv; int fd; @@ -274,13 +310,16 @@ int main(void) return 1; } rv = read(fd, buf, sizeof(buf)); - assert(rv == strlen(buf0)); + assert(rv == len); assert(memcmp(buf, buf0, strlen(buf0)) == 0); + if (g_vsyscall) { + assert(memcmp(buf + strlen(buf0), str_vsyscall, strlen(str_vsyscall)) == 0); + } } /* Test /proc/$PID/smaps */ { - char buf[1024]; + char buf[4096]; ssize_t rv; int fd; @@ -319,6 +358,10 @@ int main(void) for (i = 0; i < sizeof(S)/sizeof(S[0]); i++) { assert(memmem(buf, rv, S[i], strlen(S[i]))); } + + if (g_vsyscall) { + assert(memmem(buf, rv, str_vsyscall, strlen(str_vsyscall))); + } } /* Test /proc/$PID/smaps_rollup */ _
