Re: [PATCH v2 2/6] elf: Avoid unnecessary slowdown from profiling with audit (BZ#15533)

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 19/07/2021 11:33, Adhemerval Zanella wrote:

> diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c
> index e13a672ade..2abcfc996f 100644
> --- a/elf/dl-reloc.c
> +++ b/elf/dl-reloc.c
> @@ -181,7 +181,17 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
>  #ifdef SHARED
>    /* If we are auditing, install the same handlers we need for profiling.  */
>    if ((reloc_mode & __RTLD_AUDIT) == 0)
> -    consider_profiling |= GLRO(dl_audit) != NULL;
> +    {
> +      struct audit_ifaces *afct = GLRO(dl_audit);
> +      for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
> +	{
> +	  /* Profiling is needed only if PLT hooks are provided.  */
> +	  if (afct->ARCH_LA_PLTENTER != NULL
> +	      || afct->ARCH_LA_PLTEXIT != NULL)
> +	    consider_profiling = 1;
> +	  afct = afct->next;
> +	}
> +    }
>  #elif defined PROF

This is wrong since it disables la_symbind() for lazy resolution
if the audit modules does not provide the plt callbacks as well.
I will update the patch to now call la_symbind() on _dl_fixup() if
la_symbind() is set.