Hi,
On 02/03/2015 11:09 PM, Li Wang wrote:
>
>
>> +
>> +static void setup(void);
>> +static void cleanup(void);
>> +static void do_child(void);
>> +static void do_test(void);
>> +
>> +static const char *device;
>> +static const char *fs_type = "ext4";
>> +static int mount_flag;
>> +
>> +static int page_size;
>> +static struct tst_checkpoint checkpoint1, checkpoint2;
>> +static int bug_reproduced;
>> +
>> +char *TCID = "mmap16";
>> +int TST_TOTAL = 1; <<============
> here declare: "TST_TOTAL = 10;" will be better i think.
Nope, please see doc/test-writing-guidelines.txt:
-------------------------------------------------------------------------
'TST_TOTAL' defines total number of tests.
NOTE: The test should report 'TST_TOTAL' PASSES/FAILS on each iteration.
-------------------------------------------------------------------------
In this mmap16 test, indeed it only tests one case, so we must define
TST_TOTAL to be 1.
Regards,
Xiaoguang Wang
>
>> +
>> +int main(int ac, char **av)
>> +{
>> + int i, lc;
>> + const char *msg;
>> +
>> + msg = parse_opts(ac, av, NULL, NULL);
>> + if (msg != NULL)
>> + tst_brkm(TBROK, NULL, "OPTION PARSING ERROR - %s", msg);
>> +
>> + setup();
>> +
>> + /*
>> + * If child process was killed by SIGBUS, indeed that can not guarantee
>> + * this bug must have been fixed, If we're luckily enough, virtual
>> + * memory subsystem happen to decide that it is time to write dirty
>> + * pages, it will make mapped pages write-protect, so ->page_mkwrite()
>> + * still will be called, child process will be killed by SIGBUS, but
>> + * it's not because of above fixing patches. So here we run this test
>> + * 10 times, if once, child process exits normally, we can sure that
>> + * this bug is not fixed.
>> + */
>> + for (lc = 0; TEST_LOOPING(lc); lc++) {
>> + tst_count = 0;
>> +
>> + for (i = 0; i < SUB_LOOPCOUNT; i++)
>
> seems here should be like this:
> for (i = 0; i < TST_TOTAL； i++)
>
>
>> + do_test();
>> + }
>> +
>> + if (bug_reproduced)
>> + tst_resm(TFAIL, "Bug is reproduced!");
>> + else
>> + tst_resm(TPASS, "Bug is not reproduced!");
>> +
>> + cleanup();
>> + tst_exit();
>> +}
>> +
>> +static void do_test(void)
>> +{
>> + int fd, ret, status;
>> + pid_t child;
>> + char buf[FS_BLOCKSIZE];
>> +
>> + SAFE_TOUCH(cleanup, "testfilep", 0644, NULL);
>> + SAFE_TOUCH(cleanup, "testfilec", 0644, NULL);
>> +
>> + child = tst_fork();
>> + if (child < 0) {
>> + tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
>> + } else if (child == 0) {
>> + do_child();
>> + } else {
>> + fd = SAFE_OPEN(cleanup, "testfilep", O_RDWR);
>> + memset(buf, 'a', FS_BLOCKSIZE);
>> +
>> + TST_CHECKPOINT_PARENT_WAIT(cleanup, &checkpoint1);
>> + while (1) {
>> + ret = write(fd, buf, FS_BLOCKSIZE);
>> + if (ret < 0) {
>> + if (errno == ENOSPC) {
>> + break;
>> + } else {
>> + tst_brkm(TBROK | TERRNO, cleanup,
>> + "write failed unexpectedly");
>> + }
>> + }
>> + }
>> + SAFE_CLOSE(cleanup, fd);
>> + TST_CHECKPOINT_SIGNAL_CHILD(cleanup, &checkpoint2);
>> + }
>
> I agree with Cyril's point, the codes write in switch() will more easily to
> understand
>
> switch (child) {
> case -1:
> tst_brkm(...);
> case 0:
> do_child();
> break;
> default:
> ...
> break;
> }
>
>> +
>> + wait(&status);
>> + if (WIFSIGNALED(status) && WTERMSIG(status) == SIGBUS) {
>> + ;
>> + } else if (WIFEXITED(status) && WEXITSTATUS(status) == 1) {
>> + bug_reproduced = 1;
>> + } else {
>> + tst_brkm(TBROK | TERRNO, cleanup,
>> + "child process terminate unexpectedly");
>> + }
>> +
>> + SAFE_UNLINK(cleanup, "testfilep");
>> + SAFE_UNLINK(cleanup, "testfilec");
>> +}
>> +
>> +static void setup(void)
>> +{
>> + const char *fs_opts[3] = {"-b", "1024", NULL};
>> +
>> + tst_sig(FORK, DEF_HANDLER, NULL);
>> + tst_require_root(NULL);
>> +
>> + TEST_PAUSE;
>> + tst_tmpdir();
>> +
>> + page_size = getpagesize();
>> + if (page_size == -1)
>> + tst_brkm(TBROK | TERRNO, cleanup, "Unable to get page size");
>> +
>> + device = tst_acquire_device(cleanup);
>> + if (!device)
>> + tst_brkm(TCONF, cleanup, "Failed to obtain block device");
>> + tst_mkfs(cleanup, device, fs_type, fs_opts);
>> +
>> + SAFE_MKDIR(cleanup, MNTPOINT, 0755);
>> + /*
>> + * Disable ext4 delalloc feature, so block will be allocated
>> + * as soon as possible
>> + */
>> + if (mount(device, MNTPOINT, fs_type, 0, "nodelalloc") < 0) {
>> + tst_brkm(TBROK | TERRNO, cleanup,
>> + "mount device:%s failed", device);
>> + }
>> + mount_flag = 1;
>> +
>> + SAFE_CHDIR(cleanup, MNTPOINT);
>> + TST_CHECKPOINT_CREATE(&checkpoint1);
>> + TST_CHECKPOINT_CREATE(&checkpoint2);
>> +}
>> +
>> +static void do_child(void)
>> +{
>> + int fd, offset;
>> + char buf[FS_BLOCKSIZE];
>> + char *addr = NULL;
>> +
>> + /*
>> + * We have changed SIGBUS' handler in parent process by calling
>> + * tst_sig(FORK, DEF_HANDLER, NULL), so here just restore it.
>> + */
>> + if (signal(SIGBUS, SIG_DFL) == SIG_ERR)
>> + tst_brkm(TBROK | TERRNO, NULL, "signal(SIGBUS) failed");
>> +
>> + memset(buf, 'a', FS_BLOCKSIZE);
>> + fd = SAFE_OPEN(NULL, "testfilec", O_RDWR);
>> + SAFE_PWRITE(NULL, 1, fd, buf, FS_BLOCKSIZE, 0);
>> +
>> + /*
>> + * In case mremap() may fail because that memory area can not be
>> + * expanded at current virtual address(MREMAP_MAYMOVE is not set),
>> + * we first do a mmap(page_size * 2) operation to reserve some
>> + * free address space.
>> + */
>> + addr = (char *)SAFE_MMAP(NULL, NULL, page_size * 2, PROT_WRITE |
>> + PROT_READ, MAP_PRIVATE_EXCEPT_UCLINUX|
>> + MAP_ANONYMOUS, -1, 0);
>> + SAFE_MUNMAP(NULL, addr, page_size * 2);
>> +
>> + addr = (char *)SAFE_MMAP(NULL, addr, FS_BLOCKSIZE, PROT_WRITE |
>> + PROT_READ, MAP_SHARED, fd, 0);
>> +
>> + addr[0] = 'a';
>> +
>> + SAFE_FTRUNCATE(NULL, fd, page_size * 2);
>> + addr = mremap(addr, FS_BLOCKSIZE, 2 * page_size, 0);
>> + if (addr == MAP_FAILED)
>> + tst_brkm(TBROK | TERRNO, NULL, "mremap failed unexpectedly");
>> +
>> + /*
>> + * Let parent process consume FS free blocks as many as possible, then
>> + * there'll be no free blocks allocated for this new file mmaping for
>> + * offset starting at 1024, 2048, or 3072. If this above kernel bug
>> + * has been fixed, usually child process will killed by SIGBUS signal,
>> + * if not, the data 'A', 'B', 'C' will be silently discarded later when
>> + * kernel writepage is called, that means data corruption.
>> + */
>> + TST_CHECKPOINT_SIGNAL_PARENT(&checkpoint1);
>> + TST_CHECKPOINT_CHILD_WAIT(&checkpoint2);
>> +
>> + for (offset = FS_BLOCKSIZE; offset < page_size; offset += FS_BLOCKSIZE)
>> + addr[offset] = 'a';
>> + exit(TFAIL);
>> +}
>> +
>> +static void cleanup(void)
>> +{
>> + TEST_CLEANUP;
>> +
>> + SAFE_CHDIR(NULL, "..");
>> + if (mount_flag && tst_umount(MNTPOINT) < 0)
>> + tst_resm(TWARN | TERRNO, "umount device:%s failed", device);
>> +
>> + if (device)
>> + tst_release_device(NULL, device);
>> +
>> + tst_rmdir();
>> +}
>> --
>> 1.8.3.1
>>
>>
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> .
>
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sponsored by Intel and developed in partnership with Slashdot Media, is your
hub for all things parallel software development, from weekly thought
leadership blogs to news, videos, case studies, tutorials and more. Take a
look and join the conversation now. http://goparallel.sourceforge.net/
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