Re: [PATCH v3] firmware_loader: fix use-after-free in firmware_fallback_sysfs

[Luis Chamberlain]

On Wed, Apr 14, 2021 at 09:26:55AM -0600, Shuah Khan wrote:
> On 4/14/21 6:55 AM, Luis Chamberlain wrote:
> > In either case I documented well *why* we do these error checks
> > before sending a code to userspace on fw_sysfs_wait_timeout() since
> > otherwise it would be easy to regress that code, so please also
> > document that as I did.
> > 
> > I'll re-iterate again also:
> > 
> > 	Shuah's commit 0542ad88fbdd81bb ("firmware loader: Fix
> > 	_request_firmware_load() return val for fw load abort") also wanted to
> > 	distinguish the timeout vs -ENOMEM, but for some reason in the timeout
> > 	case -EAGAIN was being sent back to userspace. I am no longer sure if
> > 	that is a good idea, but since we started doing that at some point I
> > 	guess we want to keep that behaviour.
> > 
> > Shuah, can you think of any reason to retain -EAGAIN other than you
> > introduced it here? If there's no real good reason I think it can
> > simplify the error handling here. But, we *would* change what we do
> > to userspace... and for that reason we may have to live with it.
> > 
> 
> As I recall the reason for this patch was to be able to differentiate
> between timing out vs no memory case when driver was attempting to
> load firmware. I wish I added why to the change log.
> 
> The code seems to have changed a lot since my commit. I will take a look
> at the closely and let you know if this is still necessary late on
> today.

Shuah, *poke*

  Luis