[patch, libgomp] Fix segfault with plugin-hsa

[Tobias Burnus]

Hi all, hi Jakub,

when playing around with offloading, I got an hsa initialization error 
(/dev/... lacked write permission) and the library call returned with an 
error status – but hsa_fns.hsa_status_string_fn didn't set the message 
to the string variable.

Hence, the string variable was uninitialized and libgomp crashed when 
printing the error message; "[unknown]" is not the best HSA run-time 
message, but at least the primary message is shown and there is no crash :-)

Build and tested on x86_64-gnu-linux.

OK for the trunk and GCC 9?

Tobias


2019-09-11  Tobias Burnus  <tob...@codesourcery.com>

        * plugin/plugin-hsa.c (hsa_warn, hsa_fatal, hsa_error): Ensure
        string is initialized.

diff --git a/libgomp/plugin/plugin-hsa.c b/libgomp/plugin/plugin-hsa.c
index 80f23f9beb6..c0837d04e5d 100644
--- a/libgomp/plugin/plugin-hsa.c
+++ b/libgomp/plugin/plugin-hsa.c
@@ -289,7 +289,7 @@ hsa_warn (const char *str, hsa_status_t status)
   if (!debug)
     return;
 
-  const char *hsa_error_msg;
+  const char *hsa_error_msg = "[unknown]";
   hsa_fns.hsa_status_string_fn (status, &hsa_error_msg);
 
   fprintf (stderr, "HSA warning: %s\nRuntime message: %s", str, hsa_error_msg);
@@ -301,7 +301,7 @@ hsa_warn (const char *str, hsa_status_t status)
 static void
 hsa_fatal (const char *str, hsa_status_t status)
 {
-  const char *hsa_error_msg;
+  const char *hsa_error_msg = "[unknown]";
   hsa_fns.hsa_status_string_fn (status, &hsa_error_msg);
   GOMP_PLUGIN_fatal ("HSA fatal error: %s\nRuntime message: %s", str,
                     hsa_error_msg);
@@ -313,7 +313,7 @@ hsa_fatal (const char *str, hsa_status_t status)
 static bool
 hsa_error (const char *str, hsa_status_t status)
 {
-  const char *hsa_error_msg;
+  const char *hsa_error_msg = "[unknown]";
   hsa_fns.hsa_status_string_fn (status, &hsa_error_msg);
   GOMP_PLUGIN_error ("HSA fatal error: %s\nRuntime message: %s", str,
                     hsa_error_msg);