Re: [PATCH] usb: gadget: dummy_hcd: execute hrtimer callback in softirq context

[Alan Stern <stern@rowland.harvard.edu>]

On Mon, Jul 29, 2024 at 06:14:30PM +0200, Andrey Konovalov wrote:
> On Mon, Jul 29, 2024 at 10:26 AM Marcello Sylvester Bauer <sylv@sylv.io> wrote:
> >
> > Hi Andrey,
> 
> Hi Marcello,
> 
> > Thanks for investigating and finding the cause of this problem. I have
> > already submitted an identical patch to change the hrtimer to softirq:
> > https://lkml.org/lkml/2024/6/26/969
> 
> Ah, I missed that, that's great!
> 
> > However, your commit messages contain more useful information about the
> > problem at hand. So I'm happy to drop my patch in favor of yours.
> 
> That's very considerate, thank you. I'll leave this up to Greg - I
> don't mind using either patch.
> 
> > Btw, the same problem has also been reported by the intel kernel test
> > robot. So we should add additional tags to mark this patch as the fix.
> >
> >
> > Reported-by: kernel test robot <oliver.sang@intel.com>
> > Closes:
> > https://lore.kernel.org/oe-lkp/202406141323.413a90d2-lkp@intel.com
> > Acked-by: Marcello Sylvester Bauer <sylv@sylv.io>
> 
> Let's also add the syzbot reports mentioned in your patch:
> 
> Reported-by: syzbot+c793a7eca38803212c61@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=c793a7eca38803212c61
> Reported-by: syzbot+1e6e0b916b211bee1bd6@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=1e6e0b916b211bee1bd6
> 
> And I also found one more:
> 
> Reported-by: syzbot+edd9fe0d3a65b14588d5@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=edd9fe0d3a65b14588d5

You need to be careful about claiming that this patch will fix those bug 
reports.  At least one of them (the last one above) still fails with the 
patch applied.  See:

https://lore.kernel.org/linux-usb/ade15714-6aa3-4988-8b45-719fc9d74727@rowland.harvard.edu/

and the following response.

Alan Stern