commit 88b3228d9f6322b035fa89bb34f82d93b4190d48

Author: Martin Sebor <msebor@redhat.com>

Date:   Tue Jan 25 15:39:38 2022 -0700

    Avoid -Wuse-after-free in tests [BZ #26779].

    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

    (cherry picked from commit c094c232eb3246154265bb035182f92fe1b17ab8)

diff --git a/malloc/tst-malloc-backtrace.c b/malloc/tst-malloc-backtrace.c

index 4eb42e7f32f706e9..2ae3fb11efc245cb 100644

--- a/malloc/tst-malloc-backtrace.c

+++ b/malloc/tst-malloc-backtrace.c

@@ -20,6 +20,7 @@

 #include <stdlib.h>

 #include <support/support.h>

+#include <libc-diag.h>

 #define SIZE 4096

@@ -29,7 +30,15 @@ __attribute__((noinline))

 call_free (void *ptr)

 {

   free (ptr);

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a valid warning about using a pointer made indeterminate

+     by a prior call to free().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

   *(size_t *)(ptr - sizeof (size_t)) = 1;

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

 }

 int

diff --git a/malloc/tst-malloc-check.c b/malloc/tst-malloc-check.c

index 6650d09cf6cdde75..c5c9254a9e8936b0 100644

--- a/malloc/tst-malloc-check.c

+++ b/malloc/tst-malloc-check.c

@@ -87,7 +87,15 @@ do_test (void)

     merror ("errno is not set correctly.");

   DIAG_POP_NEEDS_COMMENT;

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a valid warning about using a pointer made indeterminate

+     by a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

   free (p);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

   p = malloc (512);

   if (p == NULL)

@@ -105,7 +113,15 @@ do_test (void)

     merror ("errno is not set correctly.");

   DIAG_POP_NEEDS_COMMENT;

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a valid warning about using a pointer made indeterminate

+     by a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

   free (p);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

   free (q);

   return errors != 0;

diff --git a/malloc/tst-malloc-too-large.c b/malloc/tst-malloc-too-large.c

index a4349a9b4c506dfc..328b4a2a4fd72cf4 100644

--- a/malloc/tst-malloc-too-large.c

+++ b/malloc/tst-malloc-too-large.c

@@ -95,7 +95,15 @@ test_large_allocations (size_t size)

   DIAG_POP_NEEDS_COMMENT;

 #endif

   TEST_VERIFY (errno == ENOMEM);

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a warning about using a pointer made indeterminate by

+     a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

   free (ptr_to_realloc);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

   for (size_t nmemb = 1; nmemb <= 8; nmemb *= 2)

     if ((size % nmemb) == 0)

@@ -113,14 +121,30 @@ test_large_allocations (size_t size)

         test_setup ();

         TEST_VERIFY (reallocarray (ptr_to_realloc, nmemb, size / nmemb) == NULL);

         TEST_VERIFY (errno == ENOMEM);

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a warning about using a pointer made indeterminate by

+     a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

         free (ptr_to_realloc);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

         ptr_to_realloc = malloc (16);

         TEST_VERIFY_EXIT (ptr_to_realloc != NULL);

         test_setup ();

         TEST_VERIFY (reallocarray (ptr_to_realloc, size / nmemb, nmemb) == NULL);

         TEST_VERIFY (errno == ENOMEM);

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a warning about using a pointer made indeterminate by

+     a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

         free (ptr_to_realloc);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

       }

     else

       break;

diff --git a/malloc/tst-obstack.c b/malloc/tst-obstack.c

index ee1385d0f764e368..7d700c4f9a86b676 100644

--- a/malloc/tst-obstack.c

+++ b/malloc/tst-obstack.c

@@ -21,8 +21,8 @@ verbose_malloc (size_t size)

 static void

 verbose_free (void *buf)

 {

-  free (buf);

   printf ("free (%p)\n", buf);

+  free (buf);

 }

 static int

diff --git a/malloc/tst-realloc.c b/malloc/tst-realloc.c

index c89ac07e192d70eb..80711beab1257ed5 100644

--- a/malloc/tst-realloc.c

+++ b/malloc/tst-realloc.c

@@ -138,8 +138,16 @@ do_test (void)

   if (ok == 0)

     merror ("first 16 bytes were not correct after failed realloc");

+#if __GNUC_PREREQ (12, 0)

+  /* Ignore a valid warning about using a pointer made indeterminate

+     by a prior call to realloc().  */

+  DIAG_IGNORE_NEEDS_COMMENT (12, "-Wuse-after-free");

+#endif

   /* realloc (p, 0) frees p (C89) and returns NULL (glibc).  */

   p = realloc (p, 0);

+#if __GNUC_PREREQ (12, 0)

+  DIAG_POP_NEEDS_COMMENT;

+#endif

   if (p != NULL)

     merror ("realloc (p, 0) returned non-NULL.");

diff --git a/support/tst-support-open-dev-null-range.c b/support/tst-support-open-dev-null-range.c

index 8e29def1ce780629..80c97e51586bf6ce 100644

--- a/support/tst-support-open-dev-null-range.c

+++ b/support/tst-support-open-dev-null-range.c

@@ -39,10 +39,11 @@ check_path (int fd)

   char file_path[PATH_MAX];

   ssize_t file_path_length

     = readlink (proc_fd_path, file_path, sizeof (file_path));

-  free (proc_fd_path);

   if (file_path_length < 0)

     FAIL_EXIT1 ("readlink (%s, %p, %zu)", proc_fd_path, file_path,

 		sizeof (file_path));

+

+  free (proc_fd_path);

   file_path[file_path_length] = '\0';

   TEST_COMPARE_STRING (file_path, "/dev/null");

 }