Fix double free on fork after hsaKmtCloseKFD

Child process hsaKmtOpenKFD() call must re-initialize global variables
copied from parent process. This includes close all file handles, free
dynamically malloc buf. Double free issue is because destroy_device_
debugging_memory() free the memory in parent process hsaKmtCloseKFD()
but don't reset it to null pointer. As a result, child process free it
again. kfd_fd is closed in parent process but don't reset to 0, so
child process close it again.

Fix: reset kfd_fd to 0 after close, reset is_device_debugged pointer to 0
after free



Change-Id: I421b3decbcaa4111298b8e599aa16940d851a58c
Signed-off-by: Philip Yang <Philip.Yang@amd.com>

src/debug.c

@@ -47,8 +47,10 @@ HSAKMT_STATUS init_device_debugging_memory(unsigned int NumNodes)
 
 void destroy_device_debugging_memory(void)
 {
-	if (is_device_debugged)
+	if (is_device_debugged) {
 		free(is_device_debugged);
+		is_device_debugged = NULL;
+	}
 }
 
 HSAKMT_STATUS HSAKMTAPI hsaKmtDbgRegister(HSAuint32 NodeId)