diff options
Diffstat (limited to 'tools/testing/selftests')
| -rw-r--r-- | tools/testing/selftests/powerpc/signal/Makefile | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/powerpc/signal/sig_sc_double_restart.c | 174 |
2 files changed, 175 insertions, 1 deletions
diff --git a/tools/testing/selftests/powerpc/signal/Makefile b/tools/testing/selftests/powerpc/signal/Makefile index 932a032bf036..d6ae54663aed 100644 --- a/tools/testing/selftests/powerpc/signal/Makefile +++ b/tools/testing/selftests/powerpc/signal/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 -TEST_GEN_PROGS := signal signal_tm sigfuz sigreturn_vdso +TEST_GEN_PROGS := signal signal_tm sigfuz sigreturn_vdso sig_sc_double_restart CFLAGS += -maltivec $(OUTPUT)/signal_tm: CFLAGS += -mhtm diff --git a/tools/testing/selftests/powerpc/signal/sig_sc_double_restart.c b/tools/testing/selftests/powerpc/signal/sig_sc_double_restart.c new file mode 100644 index 000000000000..e3972264615b --- /dev/null +++ b/tools/testing/selftests/powerpc/signal/sig_sc_double_restart.c @@ -0,0 +1,174 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Test that a syscall does not get restarted twice, handled by trap_norestart() + * + * Based on Al's description, and a test for the bug fixed in this commit: + * + * commit 9a81c16b527528ad307843be5571111aa8d35a80 + * Author: Al Viro <viro@zeniv.linux.org.uk> + * Date: Mon Sep 20 21:48:57 2010 +0100 + * + * powerpc: fix double syscall restarts + * + * Make sigreturn zero regs->trap, make do_signal() do the same on all + * paths. As it is, signal interrupting e.g. read() from fd 512 (== + * ERESTARTSYS) with another signal getting unblocked when the first + * handler finishes will lead to restart one insn earlier than it ought + * to. Same for multiple signals with in-kernel handlers interrupting + * that sucker at the same time. Same for multiple signals of any kind + * interrupting that sucker on 64bit... + */ +#define _GNU_SOURCE +#include <sys/types.h> +#include <sys/wait.h> +#include <sys/syscall.h> +#include <unistd.h> +#include <signal.h> +#include <errno.h> +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +#include "utils.h" + +static void SIGUSR1_handler(int sig) +{ + kill(getpid(), SIGUSR2); + /* + * SIGUSR2 is blocked until the handler exits, at which point it will + * be raised again and think there is a restart to be done because the + * pending restarted syscall has 512 (ERESTARTSYS) in r3. The second + * restart will retreat NIP another 4 bytes to fail case branch. + */ +} + +static void SIGUSR2_handler(int sig) +{ +} + +static ssize_t raw_read(int fd, void *buf, size_t count) +{ + register long nr asm("r0") = __NR_read; + register long _fd asm("r3") = fd; + register void *_buf asm("r4") = buf; + register size_t _count asm("r5") = count; + + asm volatile( +" b 0f \n" +" b 1f \n" +" 0: sc 0 \n" +" bns 2f \n" +" neg %0,%0 \n" +" b 2f \n" +" 1: \n" +" li %0,%4 \n" +" 2: \n" + : "+r"(_fd), "+r"(nr), "+r"(_buf), "+r"(_count) + : "i"(-ENOANO) + : "memory", "r6", "r7", "r8", "r9", "r10", "r11", "r12", "ctr", "cr0"); + + if (_fd < 0) { + errno = -_fd; + _fd = -1; + } + + return _fd; +} + +#define DATA "test 123" +#define DLEN (strlen(DATA)+1) + +int test_restart(void) +{ + int pipefd[2]; + pid_t pid; + char buf[512]; + + if (pipe(pipefd) == -1) { + perror("pipe"); + exit(EXIT_FAILURE); + } + + pid = fork(); + if (pid == -1) { + perror("fork"); + exit(EXIT_FAILURE); + } + + if (pid == 0) { /* Child reads from pipe */ + struct sigaction act; + int fd; + + memset(&act, 0, sizeof(act)); + sigaddset(&act.sa_mask, SIGUSR2); + act.sa_handler = SIGUSR1_handler; + act.sa_flags = SA_RESTART; + if (sigaction(SIGUSR1, &act, NULL) == -1) { + perror("sigaction"); + exit(EXIT_FAILURE); + } + + memset(&act, 0, sizeof(act)); + act.sa_handler = SIGUSR2_handler; + act.sa_flags = SA_RESTART; + if (sigaction(SIGUSR2, &act, NULL) == -1) { + perror("sigaction"); + exit(EXIT_FAILURE); + } + + /* Let's get ERESTARTSYS into r3 */ + while ((fd = dup(pipefd[0])) != 512) { + if (fd == -1) { + perror("dup"); + exit(EXIT_FAILURE); + } + } + + if (raw_read(fd, buf, 512) == -1) { + if (errno == ENOANO) { + fprintf(stderr, "Double restart moved restart before sc instruction.\n"); + _exit(EXIT_FAILURE); + } + perror("read"); + exit(EXIT_FAILURE); + } + + if (strncmp(buf, DATA, DLEN)) { + fprintf(stderr, "bad test string %s\n", buf); + exit(EXIT_FAILURE); + } + + return 0; + + } else { + int wstatus; + + usleep(100000); /* Hack to get reader waiting */ + kill(pid, SIGUSR1); + usleep(100000); + if (write(pipefd[1], DATA, DLEN) != DLEN) { + perror("write"); + exit(EXIT_FAILURE); + } + close(pipefd[0]); + close(pipefd[1]); + if (wait(&wstatus) == -1) { + perror("wait"); + exit(EXIT_FAILURE); + } + if (!WIFEXITED(wstatus)) { + fprintf(stderr, "child exited abnormally\n"); + exit(EXIT_FAILURE); + } + + FAIL_IF(WEXITSTATUS(wstatus) != EXIT_SUCCESS); + + return 0; + } +} + +int main(void) +{ + test_harness_set_timeout(10); + return test_harness(test_restart, "sig sys restart"); +} |