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[PATCH] Linux: Use mmap instead of malloc in dirent/tst-getdents64
- From: Florian Weimer <fweimer at redhat dot com>
- To: libc-alpha at sourceware dot org
- Date: Fri, 28 Jun 2019 10:49:16 +0200
- Subject: [PATCH] Linux: Use mmap instead of malloc in dirent/tst-getdents64
malloc dirties the entire allocated memory region due to M_PERTURB
in the test harness.
2019-06-28 Florian Weimer <fweimer@redhat.com>
* sysdeps/unix/sysv/linux/tst-getdents64.c (large_buffer_checks):
Use mmap instead of malloc. malloc with M_PERTURB writes to the
entire allocated memory range.
diff --git a/sysdeps/unix/sysv/linux/tst-getdents64.c b/sysdeps/unix/sysv/linux/tst-getdents64.c
index 24e77e04d8..8a28e6c67c 100644
--- a/sysdeps/unix/sysv/linux/tst-getdents64.c
+++ b/sysdeps/unix/sysv/linux/tst-getdents64.c
@@ -27,6 +27,7 @@
#include <support/check.h>
#include <support/support.h>
#include <support/xunistd.h>
+#include <sys/mman.h>
#include <unistd.h>
/* Called by large_buffer_checks below. */
@@ -53,8 +54,13 @@ large_buffer_checks (int fd)
size_t large_buffer_size;
if (!__builtin_add_overflow (UINT_MAX, 2, &large_buffer_size))
{
- char *large_buffer = malloc (large_buffer_size);
- if (large_buffer == NULL)
+ int flags = MAP_ANONYMOUS | MAP_PRIVATE;
+#ifdef MAP_NORESERVE
+ flags |= MAP_NORESERVE;
+#endif
+ void *large_buffer = mmap (NULL, large_buffer_size,
+ PROT_READ | PROT_WRITE, flags, -1, 0);
+ if (large_buffer == MAP_FAILED)
printf ("warning: could not allocate %zu bytes of memory,"
" subtests skipped\n", large_buffer_size);
else
@@ -65,8 +71,8 @@ large_buffer_checks (int fd)
large_buffer_check (fd, large_buffer, UINT_MAX);
large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 1);
large_buffer_check (fd, large_buffer, (size_t) UINT_MAX + 2);
+ xmunmap (large_buffer, large_buffer_size);
}
- free (large_buffer);
}
}