[bug report] drm/amdkfd: Add procfs-style information for KFD processes

[Dan Carpenter]

Hello Kent Russell,

The patch de9f26bbd384: "drm/amdkfd: Add procfs-style information for
KFD processes" from Jun 13, 2019, leads to the following static
checker warning:

	drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c:297 kfd_create_process()
	error: 'process' dereferencing possible ERR_PTR()

drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_process.c
   284           */
   285          mutex_lock(&kfd_processes_mutex);
   286  
   287          /* A prior open of /dev/kfd could have already created the process. */
   288          process = find_process(thread);
   289          if (process) {
   290                  pr_debug("Process already found\n");
   291          } else {
   292                  process = create_process(thread, filep);
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This returns error pointers.

   293  
   294                  if (!procfs.kobj)
                             ^^^^^^^^^^^
This is a global.  Can we check it earlier?


   295                          goto out;
   296  
   297                  process->kobj = kfd_alloc_struct(process->kobj);
   298                  if (!process->kobj) {
   299                          pr_warn("Creating procfs kobject failed");
   300                          goto out;

We return success on this path.

   301                  }
   302                  ret = kobject_init_and_add(process->kobj, &procfs_type,
   303                                             procfs.kobj, "%d",
   304                                             (int)process->lead_thread->pid);
   305                  if (ret) {
   306                          pr_warn("Creating procfs pid directory failed");
   307                          goto out;

No error handling.  Basically whenever there is a goto out the error
handling is suspect.  It's better to pick a name which says what the
error label does...

   308                  }
   309  
   310                  process->attr_pasid.name = "pasid";
   311                  process->attr_pasid.mode = KFD_SYSFS_FILE_MODE;
   312                  sysfs_attr_init(&process->attr_pasid);
   313                  ret = sysfs_create_file(process->kobj, &process->attr_pasid);
   314                  if (ret)
   315                          pr_warn("Creating pasid for pid %d failed",
   316                                          (int)process->lead_thread->pid);

Error handling and error code missing.

   317          }
   318  out:
   319          mutex_unlock(&kfd_processes_mutex);
   320  
   321          return process;
   322  }


regards,
dan carpenter