[PATCH] malloc: Exit early on test failure in tst-realloc

[Siddhesh Poyarekar]

On 03/03/2022 16:54, Florian Weimer via Libc-alpha wrote:
> This addresses more (correct) use-after-free warnings reported by
> GCC 12 on some targets.
> 
> Fixes commit c094c232eb3246154265bb035182f92fe1b17ab8 ("Avoid
> -Wuse-after-free in tests [BZ #26779].").
> 
> (This should fix all the remaining build-many-glibcs.py failures with
> GCC 12, with the exception of the sh4 ICE.)

LGTM.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

> 
> ---
>   malloc/tst-realloc.c | 46 +++++++++++++++-------------------------------
>   1 file changed, 15 insertions(+), 31 deletions(-)
> 
> diff --git a/malloc/tst-realloc.c b/malloc/tst-realloc.c
> index 8ce59f2602..5eb62a770f 100644
> --- a/malloc/tst-realloc.c
> +++ b/malloc/tst-realloc.c
> @@ -20,15 +20,7 @@
>   #include <stdio.h>
>   #include <string.h>
>   #include <libc-diag.h>
> -
> -static int errors = 0;
> -
> -static void
> -merror (const char *msg)
> -{
> -  ++errors;
> -  printf ("Error: %s\n", msg);
> -}
> +#include <support/check.h>
>   
>   static int
>   do_test (void)
> @@ -51,11 +43,11 @@ do_test (void)
>     save = errno;
>   
>     if (p != NULL)
> -    merror ("realloc (NULL, -1) succeeded.");
> +    FAIL_EXIT1 ("realloc (NULL, -1) succeeded.");
>   
>     /* errno should be set to ENOMEM on failure (POSIX).  */
>     if (p == NULL && save != ENOMEM)
> -    merror ("errno is not set correctly");
> +    FAIL_EXIT1 ("errno is not set correctly");
>   
>     errno = 0;
>   
> @@ -64,18 +56,18 @@ do_test (void)
>     save = errno;
>   
>     if (p == NULL)
> -    merror ("realloc (NULL, 10) failed.");
> +    FAIL_EXIT1 ("realloc (NULL, 10) failed.");
>   
>     free (p);
>   
>     p = calloc (20, 1);
>     if (p == NULL)
> -    merror ("calloc (20, 1) failed.");
> +    FAIL_EXIT1 ("calloc (20, 1) failed.");
>   
>     /* Check increasing size preserves contents (C89).  */
>     p = realloc (p, 200);
>     if (p == NULL)
> -    merror ("realloc (p, 200) failed.");
> +    FAIL_EXIT1 ("realloc (p, 200) failed.");
>   
>     c = p;
>     ok = 1;
> @@ -87,20 +79,20 @@ do_test (void)
>       }
>   
>     if (ok == 0)
> -    merror ("first 20 bytes were not cleared");
> +    FAIL_EXIT1 ("first 20 bytes were not cleared");
>   
>     free (p);
>   
>     p = realloc (NULL, 100);
>     if (p == NULL)
> -    merror ("realloc (NULL, 100) failed.");
> +    FAIL_EXIT1 ("realloc (NULL, 100) failed.");
>   
>     memset (p, 0xff, 100);
>   
>     /* Check decreasing size preserves contents (C89).  */
>     p = realloc (p, 16);
>     if (p == NULL)
> -    merror ("realloc (p, 16) failed.");
> +    FAIL_EXIT1 ("realloc (p, 16) failed.");
>   
>     c = p;
>     ok = 1;
> @@ -112,7 +104,7 @@ do_test (void)
>       }
>   
>     if (ok == 0)
> -    merror ("first 16 bytes were not correct");
> +    FAIL_EXIT1 ("first 16 bytes were not correct");
>   
>     /* Check failed realloc leaves original untouched (C89).  */
>     DIAG_PUSH_NEEDS_COMMENT;
> @@ -124,7 +116,7 @@ do_test (void)
>     c = realloc (p, -1);
>     DIAG_POP_NEEDS_COMMENT;
>     if (c != NULL)
> -    merror ("realloc (p, -1) succeeded.");
> +    FAIL_EXIT1 ("realloc (p, -1) succeeded.");
>   
>     c = p;
>     ok = 1;
> @@ -136,29 +128,21 @@ do_test (void)
>       }
>   
>     if (ok == 0)
> -    merror ("first 16 bytes were not correct after failed realloc");
> +    FAIL_EXIT1 ("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.");
> +    FAIL_EXIT1 ("realloc (p, 0) returned non-NULL.");
>   
>     /* realloc (NULL, 0) acts like malloc (0) (glibc).  */
>     p = realloc (NULL, 0);
>     if (p == NULL)
> -    merror ("realloc (NULL, 0) returned NULL.");
> +    FAIL_EXIT1 ("realloc (NULL, 0) returned NULL.");
>   
>     free (p);
>   
> -  return errors != 0;
> +  return 0;
>   }
>   
>   #define TEST_FUNCTION do_test ()
>