Re: [PATCH] usb: dwc3: Fix debugfs creation flow

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Jun 17, 2021 at 09:14:37AM +0000, Minas Harutyunyan wrote:
> Hi Greg,
> 
> On 6/17/2021 11:33 AM, Greg Kroah-Hartman wrote:
> > On Thu, Jun 17, 2021 at 07:11:33AM +0000, Minas Harutyunyan wrote:
> >> Hi Greg,
> >>
> >> On 6/17/2021 10:10 AM, Greg Kroah-Hartman wrote:
> >>> On Wed, Jun 16, 2021 at 10:56:02PM -0700, Minas Harutyunyan wrote:
> >>>> Creation EP's debugfs called earlier than debugfs folder for dwc3
> >>>> device created. As result EP's debugfs are created in '/sys/kernel/debug'
> >>>> instead of '/sys/kernel/debug/usb/dwc3.1.auto'.
> >>>>
> >>>> Moved dwc3_debugfs_init() function call before calling
> >>>> dwc3_core_init_mode() to allow create dwc3 debugfs parent before
> >>>> creating EP's debugfs's.
> >>>>
> >>>> Fixes: 8562d5bfc0fc ("USB: dwc3: remove debugfs root dentry storage")
> >>>> Signed-off-by: Minas Harutyunyan <hminas@synopsys.com>
> >>>> ---
> >>>>    drivers/usb/dwc3/core.c | 3 ++-
> >>>>    1 file changed, 2 insertions(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> >>>> index e0a8e796c158..ba74ad7f6995 100644
> >>>> --- a/drivers/usb/dwc3/core.c
> >>>> +++ b/drivers/usb/dwc3/core.c
> >>>> @@ -1620,17 +1620,18 @@ static int dwc3_probe(struct platform_device *pdev)
> >>>>    	}
> >>>>    
> >>>>    	dwc3_check_params(dwc);
> >>>> +	dwc3_debugfs_init(dwc);
> >>>>    
> >>>>    	ret = dwc3_core_init_mode(dwc);
> >>>>    	if (ret)
> >>>>    		goto err5;
> >>>>    
> >>>> -	dwc3_debugfs_init(dwc);
> >>>>    	pm_runtime_put(dev);
> >>>>    
> >>>>    	return 0;
> >>>>    
> >>>>    err5:
> >>>> +	dwc3_debugfs_exit(dwc);
> >>>>    	dwc3_event_buffers_cleanup(dwc);
> >>>>    
> >>>>    	usb_phy_shutdown(dwc->usb2_phy);
> >>>>
> >>>> base-commit: 1da8116eb0c5dfc05cfb89896239badb18c4daf3
> >>>
> >>> I thought we fixed this already in usb-next and usb-linus, right?  Where
> >>> are you seeing this problem happening?
> >>
> >> I faced this issue on 5.13.0-rc6. Patch "USB: dwc3: remove debugfs root
> >> dentry storage" introduced this issue, because of debugfs_lookup()
> >> function. I don't see any fix in usb-next.
> > 
> > 4bf584a03eec ("usb: dwc3: core: fix kernel panic when do reboot") in
> > linux-next "should" solve this issue.  Or it was supposed to.  I
> > thought.  I'm getting confused about this problem these days...
> 
> No, 4bf584a03eec ("usb: dwc3: core: fix kernel panic when do reboot") 
> fix another thing.
> > 
> > The commit you reference above in the fixes line is NOT in 5.13-rc6, so
> > how can this commit fix a problem in 5.13-rc6?
> 
> I see that commit in your "usb-next" below "Merge tag 'v5.13-rc6'":
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git/log/?qt=grep&q=&h=usb-next

Yes, but that is NOT in 5.13-rc6, so your above comment does not make
sense to me.

So, to be specific, what commit causes this problem, that this patch
fixes?

thanks,

greg k-h