On Fri, Mar 19, 2021 at 10:54:48AM +0100, Dmitry Vyukov wrote: > .On Fri, Mar 19, 2021 at 10:44 AM syzbot > <syzbot+f09a12b2c77bfbbf5...@syzkaller.appspotmail.com> wrote: > > syzbot found the following issue on: > > > > HEAD commit: 8b12a62a Merge tag 'drm-fixes-2021-03-19' of git://anongit.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=17e815aed00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=cfeed364fc353c32 > > dashboard link: https://syzkaller.appspot.com/bug?extid=f09a12b2c77bfbbf51bd > > userspace arch: arm > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+f09a12b2c77bfbbf5...@syzkaller.appspotmail.com > > > +Mark, arm > It did not get far with CONFIG_CONTEXT_TRACKING_FORCE (kernel doesn't boot).
It seems that the path: context_tracking_user_enter() user_enter() context_tracking_enter() __context_tracking_enter() vtime_user_enter() expects preemption to be disabled. It effectively is, because local interrupts are disabled by context_tracking_enter(). However, the requirement for preemption to be disabled is not documented... so shrug. Maybe someone can say what the real requirements are here. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!