Hi Arnd, On Sat, 27 May 2023 at 15:03, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Sat, May 27, 2023, at 05:49, Kuniyuki Iwashima wrote: > > From: Jakub Kicinski <kuba@xxxxxxxxxx> > > Date: Fri, 26 May 2023 20:16:07 -0700 > >> On Wed, 24 May 2023 13:24:15 +0530 Naresh Kamboju wrote: > >> > While running selftests: net: udpgso_bench.sh on qemu-x86_64 the following > >> > kernel crash noticed on stable rc 6.3.4-rc2 kernel. > >> > >> Can you repro this or it's just a one-off? > >> > >> Adding some experts to CC. > > > > FWIW, I couldn't reproduce it on my x86_64 QEMU setup & 6.4.0-rc3 > > at least 5 times, so maybe one-off ? > > This looks like one of several spurious reports that lkft has produced > recently, where an 'int3' trap instruction is executed in a function > that is live-patched, but at a point where the int3 is not expected. > > Anders managed to get a reproducer for one of these on his manchine > yesterday, and has narrowed it down to failing on qemu-7.2.2 but > not failing on qemu-8.0. This is an added advantage to tests on multiple qemu versions and comparing the difference in test results. Thanks, Anders. > > The current theory right now is that this is a qemu bug when > dealing with self-modifying x86 code that has been fixed in > qemu-8.0 already, and my suggestion would be to ignore all bugs > found by lkft that involve an 'int3' trap, and instead change > the lkft setup to use either qemu-8.0 or run the test systems > in kvm (which would also be much faster and save resources). I will send out an update to ignore the 'int3' trap email reports. > > Someone still needs to get to the bottom of this bug to see > if it's in qemu or in the kernel livepatching code, but I'm > sure it has nothing to do with the ipv6 stack. Thank you Arnd. - Naresh > Arnd
