On Tue, Aug 27, 2024 at 02:02:00AM +0200, Andrey Konovalov wrote: > On Mon, Jul 29, 2024 at 4:23 AM <andrey.konovalov@xxxxxxxxx> wrote: > > > > From: Andrey Konovalov <andreyknvl@xxxxxxxxx> > > > > Commit a7f3813e589f ("usb: gadget: dummy_hcd: Switch to hrtimer transfer > > scheduler") switched dummy_hcd to use hrtimer and made the timer's > > callback be executed in the hardirq context. > > > > With that change, __usb_hcd_giveback_urb now gets executed in the hardirq > > context, which causes problems for KCOV and KMSAN. > > > > One problem is that KCOV now is unable to collect coverage from > > the USB code that gets executed from the dummy_hcd's timer callback, > > as KCOV cannot collect coverage in the hardirq context. > > > > Another problem is that the dummy_hcd hrtimer might get triggered in the > > middle of a softirq with KCOV remote coverage collection enabled, and that > > causes a WARNING in KCOV, as reported by syzbot. (I sent a separate patch > > to shut down this WARNING, but that doesn't fix the other two issues.) > > > > Finally, KMSAN appears to ignore tracking memory copying operations > > that happen in the hardirq context, which causes false positive > > kernel-infoleaks, as reported by syzbot. > > > > Change the hrtimer in dummy_hcd to execute the callback in the softirq > > context. > > > > Reported-by: syzbot+2388cdaeb6b10f0c13ac@xxxxxxxxxxxxxxxxxxxxxxxxx > > Closes: https://syzkaller.appspot.com/bug?extid=2388cdaeb6b10f0c13ac > > Reported-by: syzbot+17ca2339e34a1d863aad@xxxxxxxxxxxxxxxxxxxxxxxxx > > Closes: https://syzkaller.appspot.com/bug?extid=17ca2339e34a1d863aad > > Fixes: a7f3813e589f ("usb: gadget: dummy_hcd: Switch to hrtimer transfer scheduler") > > Cc: stable@xxxxxxxxxxxxxxx > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxx> > > Hi Greg, > > Could you pick up either this or Marcello's patch > (https://lkml.org/lkml/2024/6/26/969)? In case they got lost. Both are lost now, (and please use lore.kernel.org, not lkml.org), can you resend the one that you wish to see accepted? thanks, greg k-h