Re: [PATCH] Skip VDSO when reading SO list

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Mon, 19 Aug 2013 16:44:13 +0200, Andreas Arnez wrote:
> 2013-08-19  Andreas Arnez  <arnez@linux.vnet.ibm.com>
> 
> 	* solib-svr4.c (svr4_read_so_list): Skip the VDSO when reading
                                                     vDSO
> 	link map entries.

Could you include here the testcase from:
	http://pkgs.fedoraproject.org/cgit/gdb.git/tree/gdb-core-open-vdso-warning.patch


> Index: gdb/gdb/solib-svr4.c
> ===================================================================
> --- gdb.orig/gdb/solib-svr4.c
> +++ gdb/gdb/solib-svr4.c
> @@ -1310,6 +1310,7 @@ static int
>  svr4_read_so_list (CORE_ADDR lm, CORE_ADDR prev_lm,
>  		   struct so_list ***link_ptr_ptr, int ignore_first)
>  {
> +  struct so_list *first = NULL;
>    CORE_ADDR next_lm;
>  
>    for (; lm != 0; prev_lm = lm, lm = next_lm)
> @@ -1349,10 +1350,22 @@ svr4_read_so_list (CORE_ADDR lm, CORE_AD
>  	{
>  	  struct svr4_info *info = get_svr4_info ();
>  
> +	  first = new;
>  	  info->main_lm_addr = new->lm_info->lm_addr;
>  	  do_cleanups (old_chain);
>  	  continue;
>  	}
> +
> +      /* The l_name of a VDSO sometimes lies in read-only memory that
                            vDSO
> +	 is excluded from a core dump.  In order to avoid the "can't
> +	 read pathname" warning, we try to identify the VDSO.  One
                                                        vDSO
> +	 criteria is that the l_name address matches that of the main
> +	 executable.  */
> +      if (first && new->lm_info->l_name == first->lm_info->l_name)

Here should be also '&& ignore_first'.


> +	{
> +	  do_cleanups (old_chain);
> +	  continue;
> +	}

And move this block below so that the condition is evaluated only if
target_read_string has really failed.

The purpose is that no workarounds should complicate the code in the case the
system components are already bug-free (after glibc gets fixed).


>  
>        /* Extract this shared object's name.  */
>        target_read_string (new->lm_info->l_name, &buffer,


Please make one new post after the updates.


Thanks,
Jan