On Wed, Apr 16, 2025 at 08:40:17PM +0200, Thomas Weißschuh wrote:
> Both constructors and main() may be executed with different function
> signatures than they are actually using.
> This is intentional but trips up UBSAN.
>
> Disable the function sanitizer of UBSAN in _start_c().
>
> Signed-off-by: Thomas Weißschuh <[email protected]>
> ---
> tools/include/nolibc/crt.h | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
> index
> c4b10103bbec50f1a3a0a4562e34fdbd1b43ce6f..961cfe777c3564e705dfdd581de828b374d05b0b
> 100644
> --- a/tools/include/nolibc/crt.h
> +++ b/tools/include/nolibc/crt.h
> @@ -7,6 +7,8 @@
> #ifndef _NOLIBC_CRT_H
> #define _NOLIBC_CRT_H
>
> +#include "compiler.h"
> +
> char **environ __attribute__((weak));
> const unsigned long *_auxv __attribute__((weak));
>
> @@ -25,6 +27,9 @@ extern void (*const __fini_array_end[])(void)
> __attribute__((weak));
>
> void _start_c(long *sp);
> __attribute__((weak,used))
> +#if __nolibc_has_feature(undefined_behavior_sanitizer)
> + __attribute__((no_sanitize("function")))
> +#endif
I'm wondering if it wouldn't be more reliable with:
#if __nolibc_has_attribute(no_sanitize)
__attribute__((no_sanitize("function")))
#endif
Because in the end, what you want is to always place that attribute
whenever it's supported, no ?
> void _start_c(long *sp)
> {
> long argc;
Willy
