Re: [gomp4] libgomp: plugin for non-shared memory host execution

[Thomas Schwinge <thomas at codesourcery dot com>]

Hi!

On Wed, 19 Feb 2014 17:10:15 +0100, I wrote:
>     $ gcc -m64 -Wall -Wextra -shared -o libgomp-plugin-host.so.1 [...]/libgomp/plugin-host.c -fPIC -O -DDEBUG
> 
> ..., and then set LIBGOMP_PLUGIN_PATH=$PWD in the environment.

If putting plugins for several architectures into the same directory (as
required for 32-bit as well as 64-bit x86 GNU/Linux testing,
ÂRUNTESTFLAGS='--target_board=unix\{,-m32\}'Â), libgomp will crash when
loading the incompatible library; a bug that I introduced:

> commit 8495aab54fb244ef2643e43eb3e91a092ff0b14e
> Author: Thomas Schwinge <thomas@codesourcery.com>, James Norris <jnorris@codesourcery.com>
> Date:   Wed Feb 19 16:53:14 2014 +0100
> 
>     libgomp: plugin for non-shared memory host execution.

> --- libgomp/target.c
> +++ libgomp/target.c
> @@ -608,28 +618,43 @@ static bool
>  gomp_load_plugin_for_device (struct gomp_device_descr *device,
>  			     const char *plugin_name)
>  {
> -  if (!device || !plugin_name)
> -    return false;
> -
> -  device->plugin_handle = dlopen (plugin_name, RTLD_LAZY);
> -  if (!device->plugin_handle)
> -    return false;
> +  char *err = NULL;
>  
>    /* Clear any existing error.  */
>    dlerror ();
>  
> +  device->plugin_handle = dlopen (plugin_name, RTLD_LAZY);
> +  if (!device->plugin_handle)
> +    {
> +      err = dlerror ();
> +      goto out;

> + out:
> +  if (err != NULL)
>      {
> +      gomp_error ("while loading %s: %s", plugin_name, err);
>        dlclose (device->plugin_handle);
> -      return false;
>      }
> -
> -  return true;
> +  return err == NULL;

Fixed in r207940 as follows:

commit 4b51d1f28358bf60e96c4d6f3c78f1d7d52c4061
Author: tschwinge <tschwinge@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Thu Feb 20 11:03:13 2014 +0000

    libgomp: Avoid potential crash in plugin error handling.
    
    	* target.c (gomp_load_plugin_for_device): Don't call dlcose if
    	dlopen failed.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gomp-4_0-branch@207940 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git libgomp/ChangeLog.gomp libgomp/ChangeLog.gomp
index c764b17..3dffde4 100644
--- libgomp/ChangeLog.gomp
+++ libgomp/ChangeLog.gomp
@@ -1,4 +1,9 @@
 2014-02-20  Thomas Schwinge  <thomas@codesourcery.com>
+
+	* target.c (gomp_load_plugin_for_device): Don't call dlcose if
+	dlopen failed.
+
+2014-02-20  Thomas Schwinge  <thomas@codesourcery.com>
 	    James Norris  <jnorris@codesourcery.com>
 
 	* plugin-host.c: New file.
diff --git libgomp/target.c libgomp/target.c
index 83fcbd2..a6a5505 100644
--- libgomp/target.c
+++ libgomp/target.c
@@ -647,7 +647,8 @@ gomp_load_plugin_for_device (struct gomp_device_descr *device,
   if (err != NULL)
     {
       gomp_error ("while loading %s: %s", plugin_name, err);
-      dlclose (device->plugin_handle);
+      if (device->plugin_handle)
+	dlclose (device->plugin_handle);
     }
   return err == NULL;
 }


GrÃÃe,
 Thomas

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