Re: [PATCH] drm/amdkfd: Do not fail process debugfs setup on debugfs errors

[Dan Carpenter <error27@gmail.com>]

On Fri, Jul 10, 2026 at 09:47:32PM +0800, Zhu, Lingshan wrote:
> On 7/10/2026 7:29 PM, Srinivasan Shanmugam wrote:
> 
> > debugfs is intended for debugging only, and failures to create debugfs
> > entries should not affect normal operation.
> >
> > Remove the check for debugfs_create_dir() in kfd_debugfs_add_process().
> > If debugfs entries cannot be created, continue without them instead of
> > reporting an unnecessary error.
> >
> > Fixes: 22ab1bb3994a ("amdkfd: expose pasid of secondary contexts by debugfs")
> > Reported-by: Dan Carpenter <error27@gmail.com>
> > Cc: Zhu Lingshan <lingshan.zhu@amd.com>
> > Cc: Felix Kuehling <felix.kuehling@amd.com>
> > Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
> > ---
> >  drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c | 4 ----
> >  1 file changed, 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c b/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c
> > index 02673f01b448..7c5bc9c4559a 100644
> > --- a/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c
> > +++ b/drivers/gpu/drm/amd/amdkfd/kfd_debugfs.c
> > @@ -211,10 +211,6 @@ int kfd_debugfs_add_process(struct kfd_process *p)
> >  		entry->proc_dentry = debugfs_create_dir(name,
> >  							primary_entry->proc_dentry);
> >  	}
> > -	if (IS_ERR_OR_NULL(entry->proc_dentry)) {
> > -		ret = entry->proc_dentry ? PTR_ERR(entry->proc_dentry) : -ENOMEM;
> > -		goto err_free_entry;
> > -	}
> 
> We need this check because debugfs_create_dir() may fail.
> Removing this check leads to entry leaking when fail.
> 

Debugfs functions aren't supposed to be checked.  Drivers aren't
supposed to rely on debugfs so it's not required.  If debugfs is
failing then you are pretty much screwed anyway.

I have a blog about the history of this:
https://staticthinking.wordpress.com/2023/07/24/debugfs-functions-are-not-supposed-to-be-checked/

This code is inside #if defined(CONFIG_DEBUG_FS) so the check
isn't harmful except that it sets a bad example.  Back in the day,
this used to be a source of pain for me so Greg made it hard to
write a correct check unless you have the #ifdef.  It's to
discourage checking.

regards,
dan carpenter