Re: [PATCH] nptl: Open libgcc.so with RTLD_NOW during pthread_cancel

[Carlos O'Donell <carlos@redhat.com>]

On 01/10/2018 02:49 AM, Florian Weimer wrote:
> Disabling lazy binding reduces stack usage during unwinding.
> 
> Note that RTLD_NOW only makes a difference if libgcc.so has not
> already been loaded, so this is only a partial fix.
> 
> 2018-01-10  Florian Weimer  <fweimer@redhat.com>
> 
> 	[BZ #22636]
> 	* sysdeps/nptl/unwind-forcedunwind.c (pthread_cancel_init): Open
> 	libgcc.so with RTLD_NOW, to avoid lazy binding during unwind.
> 
> diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c
> index ab4350de99..67b8e74b53 100644
> --- a/sysdeps/nptl/unwind-forcedunwind.c
> +++ b/sysdeps/nptl/unwind-forcedunwind.c
> @@ -49,7 +49,7 @@ pthread_cancel_init (void)
>        return;
>      }
>  
> -  handle = __libc_dlopen (LIBGCC_S_SO);
> +  handle = __libc_dlopen_mode (LIBGCC_S_SO, RTLD_NOW | __RTLD_DLOPEN);
>  
>    if (handle == NULL
>        || (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL
> 

Should we not also do this for sysdeps/gnu/unwind-resume.c ?

-- 
Cheers,
Carlos.