123 lines
2.6 KiB
C
123 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) 2015 SUSE Linux. All Rights Reserved.
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* Author: Jan Kara <jack@suse.cz>
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*
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* DESCRIPTION
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* Test for inotify mark destruction race.
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*
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* Kernels prior to 4.2 have a race when inode is being deleted while
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* inotify group watching that inode is being torn down. When the race is
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* hit, the kernel crashes or loops.
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*
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* The problem has been fixed by commit:
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* 8f2f3eb59dff "fsnotify: fix oops in fsnotify_clear_marks_by_group_flags()".
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*/
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#include "config.h"
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <time.h>
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#include <signal.h>
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <sys/syscall.h>
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#include "tst_test.h"
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#include "inotify.h"
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#if defined(HAVE_SYS_INOTIFY_H)
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#include <sys/inotify.h>
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/* Number of test loops to run the test for */
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#define TEARDOWNS 400
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/* Number of files to test (must be > 1) */
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#define FILES 5
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#define PROCFILE "/proc/sys/fs/inotify/max_user_instances"
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static char names[FILES][PATH_MAX];
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static pid_t pid;
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static int old_proc_limit;
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static void setup(void)
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{
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int i;
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for (i = 0; i < FILES; i++)
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sprintf(names[i], "fname_%d", i);
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SAFE_FILE_SCANF(PROCFILE, "%d", &old_proc_limit);
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if (old_proc_limit >= 0 && old_proc_limit < TEARDOWNS)
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SAFE_FILE_PRINTF(PROCFILE, "%d", TEARDOWNS + 128);
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}
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static void verify_inotify(void)
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{
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int inotify_fd, fd;
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int i, tests;
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pid = SAFE_FORK();
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if (pid == 0) {
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while (1) {
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for (i = 0; i < FILES; i++) {
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fd = SAFE_OPEN(names[i], O_CREAT | O_RDWR, 0600);
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SAFE_CLOSE(fd);
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}
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for (i = 0; i < FILES; i++)
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SAFE_UNLINK(names[i]);
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}
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}
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for (tests = 0; tests < TEARDOWNS; tests++) {
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inotify_fd = SAFE_MYINOTIFY_INIT1(O_NONBLOCK);
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for (i = 0; i < FILES; i++) {
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/*
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* Both failure and success are fine since
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* files are being deleted in parallel - this
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* is what provokes the race we want to test
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* for...
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*/
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myinotify_add_watch(inotify_fd, names[i], IN_MODIFY);
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}
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SAFE_CLOSE(inotify_fd);
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}
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/* We survived for given time - test succeeded */
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tst_res(TPASS, "kernel survived inotify beating");
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/* Kill the child creating / deleting files and wait for it */
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SAFE_KILL(pid, SIGKILL);
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pid = 0;
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SAFE_WAIT(NULL);
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}
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static void cleanup(void)
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{
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if (pid) {
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SAFE_KILL(pid, SIGKILL);
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SAFE_WAIT(NULL);
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}
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SAFE_FILE_PRINTF(PROCFILE, "%d", old_proc_limit);
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}
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static struct tst_test test = {
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.timeout = 600,
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.needs_root = 1,
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.needs_tmpdir = 1,
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.forks_child = 1,
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.setup = setup,
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.cleanup = cleanup,
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.test_all = verify_inotify,
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};
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#else
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TST_TEST_TCONF("system doesn't have required inotify support");
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#endif
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