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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2017 Google, Inc. All Rights Reserved.
* Author: Eric Biggers <ebiggers@google.com>
*
* t_encrypted_d_revalidate
*
* Test that ->d_revalidate() for encrypted dentries doesn't oops the
* kernel by incorrectly not dropping out of RCU mode. To do this, try
* to look up a negative dentry while another thread deletes its parent
* directory. Fixed by commit 03a8bb0e53d9 ("ext4/fscrypto: avoid RCU
* lookup in d_revalidate").
*
* This doesn't always reproduce reliably, but we give it a few seconds.
*/
#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#define TIMEOUT 10
#define DIR_NAME "dir"
#define FILE_NAME DIR_NAME "/file"
static volatile sig_atomic_t timed_out = 0;
static void alarm_handler(int sig)
{
timed_out = 1;
}
static void __attribute__((noreturn))
die(int err, const char *msg)
{
fprintf(stderr, "ERROR: %s", msg);
if (err)
fprintf(stderr, ": %s", strerror(err));
fputc('\n', stderr);
exit(1);
}
static void *stat_thread(void *_arg)
{
struct stat stbuf;
for (;;) {
if (stat(FILE_NAME, &stbuf) == 0)
die(0, "stat should have failed");
if (errno != ENOENT)
die(errno, "stat");
}
}
int main(int argc, char *argv[])
{
long ncpus;
long num_stat_threads;
long i;
struct stat stbuf;
if (argc != 2) {
fprintf(stderr, "Usage: %s DIR\n", argv[0]);
return 2;
}
if (chdir(argv[1]) != 0)
die(errno, "chdir");
ncpus = sysconf(_SC_NPROCESSORS_ONLN);
if (ncpus > 1)
num_stat_threads = ncpus - 1;
else
num_stat_threads = 1;
for (i = 0; i < num_stat_threads; i++) {
pthread_t thread;
int err;
err = pthread_create(&thread, NULL, stat_thread, NULL);
if (err)
die(err, "pthread_create");
}
if (signal(SIGALRM, alarm_handler) == SIG_ERR)
die(errno, "signal");
alarm(TIMEOUT);
while (!timed_out) {
if (mkdir(DIR_NAME, 0777) != 0)
die(errno, "mkdir");
if (stat(FILE_NAME, &stbuf) == 0)
die(0, "stat should have failed");
if (errno != ENOENT)
die(errno, "stat");
if (rmdir(DIR_NAME) != 0)
die(errno, "rmdir");
}
printf("t_encrypted_d_revalidate finished\n");
return 0;
}
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