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

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

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...

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?

still confused,

greg k-h