A test for a corner-case that some pmaps get wrong.

2 files changed, 79 insertions, 0 deletions

diff --git a/regress/sys/uvm/mmap_mod/Makefile b/regress/sys/uvm/mmap_mod/Makefile
new file mode 100644
index 00000000000..336408c1ada
--- /dev/null
+++ b/regress/sys/uvm/mmap_mod/Makefile
@@ -0,0 +1,5 @@
+#	$OpenBSD: Makefile,v 1.1 2007/05/21 07:27:37 art Exp $
+
+PROG=mmap_mod
+
+.include <bsd.regress.mk>
diff --git a/regress/sys/uvm/mmap_mod/mmap_mod.c b/regress/sys/uvm/mmap_mod/mmap_mod.c
new file mode 100644
index 00000000000..eb931ad24f5
--- /dev/null
+++ b/regress/sys/uvm/mmap_mod/mmap_mod.c
@@ -0,0 +1,74 @@
+/*	$OpenBSD: mmap_mod.c,v 1.1 2007/05/21 07:27:37 art Exp $	*/
+
+/*
+ * Public domain. 2007, Artur Grabowski <art@openbsd.org>
+ */
+
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <err.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+/*
+ * Test a corner case where a pmap can lose mod/ref bits after unmapping
+ * and remapping a page.
+ */
+int
+main()
+{
+	char name[20] = "/tmp/fluff.XXXXXX";
+	char *buf, *pat;
+	size_t ps;
+	int fd;
+
+	ps = getpagesize();
+
+	if ((fd = mkstemp(name)) == -1)
+		err(1, "mkstemp");
+
+	if (unlink(name) == -1)
+		err(1, "unlink");
+
+	if (ftruncate(fd, ps))
+		err(1, "ftruncate");
+
+	if ((pat = malloc(ps)) == NULL)
+		err(1, "malloc");
+
+	memset(pat, 'a', ps);
+
+	if (pwrite(fd, pat, ps, 0) != ps)
+		err(1, "write");
+
+	buf = mmap(NULL, ps, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, fd, 0);
+	if (buf == MAP_FAILED)
+		err(1, "mmap");
+
+	if (*buf != 'a')
+		errx(1, "mapped area - no file data ('%c' != 'a')", *buf);
+
+	memset(buf, 'x', ps);
+
+	if (munmap(buf, ps) == -1)
+		err(1, "munmap");
+
+	buf = mmap(NULL, ps, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, fd, 0);
+	if (buf == MAP_FAILED)
+		err(1, "mmap 2");
+
+	if (*buf != 'x')
+		errx(1, "mapped area lost modifications ('%c' != 'x')", *buf);
+
+	if (msync(buf, ps, MS_SYNC) == -1)
+		err(1, "msync");
+
+	if (pread(fd, pat, ps, 0) != ps)
+		err(1, "pread");
+
+	if (*pat != 'x')
+		errx(1, "synced area lost modifications ('%c' != 'x')", *pat);
+
+	return (0);
+}