This data corruption fixed by:
commit 90a8020278c1598fafd071736a0846b38510309c
Author: Jan Kara <j...@suse.cz>
Date: Wed Oct 1 21:49:18 2014 -0400
vfs: fix data corruption when blocksize < pagesize for mmaped data
and this test is written to run in ext4 filesystem(with mount option
'nodelalloc'),
so there is another fixing patch needed:
commit d6320cbfc92910a3e5f10c42d98c231c98db4f60
Author: Jan Kara <j...@suse.cz>
Date: Wed Oct 1 21:49:46 2014 -0400
ext4: fix mmap data corruption when blocksize < pagesize
Signed-off-by: Xiaoguang Wang <wangxg.f...@cn.fujitsu.com>
---
runtest/ltplite | 1 +
runtest/stress.part3 | 1 +
runtest/syscalls | 1 +
testcases/kernel/syscalls/.gitignore | 1 +
testcases/kernel/syscalls/mmap/mmap16.c | 247 ++++++++++++++++++++++++++++++++
5 files changed, 251 insertions(+)
create mode 100644 testcases/kernel/syscalls/mmap/mmap16.c
diff --git a/runtest/ltplite b/runtest/ltplite
index 1457908..5d6c815 100644
--- a/runtest/ltplite
+++ b/runtest/ltplite
@@ -449,6 +449,7 @@ mmap06 mmap06
mmap07 mmap07
mmap08 mmap08
mmap09 mmap09
+mmap16 mmap16
modify_ldt01 modify_ldt01
modify_ldt02 modify_ldt02
diff --git a/runtest/stress.part3 b/runtest/stress.part3
index 368c640..48fcc5f 100644
--- a/runtest/stress.part3
+++ b/runtest/stress.part3
@@ -382,6 +382,7 @@ mmap06 mmap06
mmap07 mmap07
mmap08 mmap08
mmap09 mmap09
+mmap16 mmap16 -i 5
modify_ldt01 modify_ldt01
modify_ldt02 modify_ldt02
diff --git a/runtest/syscalls b/runtest/syscalls
index 44969f3..4e780d7 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -587,6 +587,7 @@ mmap14 mmap14
# test is broken, mask it for now.
#mmap11 mmap11 -i 30000
mmap15 mmap15
+mmap16 mmap16
modify_ldt01 modify_ldt01
modify_ldt02 modify_ldt02
diff --git a/testcases/kernel/syscalls/.gitignore
b/testcases/kernel/syscalls/.gitignore
index 92c0bf5..b443fd8 100644
--- a/testcases/kernel/syscalls/.gitignore
+++ b/testcases/kernel/syscalls/.gitignore
@@ -533,6 +533,7 @@
/mmap/mmap13
/mmap/mmap14
/mmap/mmap15
+/mmap/mmap16
/modify_ldt/modify_ldt01
/modify_ldt/modify_ldt02
/modify_ldt/modify_ldt03
diff --git a/testcases/kernel/syscalls/mmap/mmap16.c
b/testcases/kernel/syscalls/mmap/mmap16.c
new file mode 100644
index 0000000..7ce1544
--- /dev/null
+++ b/testcases/kernel/syscalls/mmap/mmap16.c
@@ -0,0 +1,247 @@
+/*
+ * Copyright (c) 2015 Fujitsu Ltd.
+ * Author: Xiaoguang Wang <wangxg.f...@cn.fujitsu.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ */
+
+/*
+ * This is a regression test for commit:
+ * http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
+ * commit/?id=90a8020
+ * http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
+ * commit/?id=d6320cb
+ */
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <sys/mount.h>
+#include <sys/mman.h>
+
+#include "usctest.h"
+#include "test.h"
+#include "safe_macros.h"
+
+#define MNTPOINT "mntpoint"
+#define FS_BLOCKSIZE 1024
+#define SUB_LOOPCOUNT 10
+
+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;
+
+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++)
+ 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();
+ switch (child) {
+ case -1:
+ tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
+ case 0:
+ do_child();
+ default:
+ 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);
+ }
+
+ wait(&status);
+ if (WIFEXITED(status) && WEXITSTATUS(status) == 1) {
+ bug_reproduced = 1;
+ } else {
+ /*
+ * If child process was killed by SIGBUS, bug is not reproduced.
+ */
+ if (!WIFSIGNALED(status) || WTERMSIG(status) != SIGBUS) {
+ 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
+ */
+ SAFE_MOUNT(cleanup, device, MNTPOINT, fs_type, 0, "nodelalloc");
+ 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 = 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 = 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';
+
+ SAFE_MUNMAP(NULL, addr, 2 * page_size);
+ SAFE_CLOSE(NULL, fd);
+ exit(TFAIL);
+}
+
+static void cleanup(void)
+{
+ TEST_CLEANUP;
+
+ if (chdir(".."))
+ tst_resm(TWARN | TERRNO, "chdir('..') failed");
+ 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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