On Wed, Sep 30, 2020 at 6:31 PM Borislav Petkov <b...@alien8.de> wrote: > > On Wed, Sep 30, 2020 at 06:23:44PM +0200, Dmitry Vyukov wrote: > > Here is the answer: > > https://github.com/google/syzkaller/blob/master/tools/create-gce-image.sh#L189 > > > > # rodata=n: mark_rodata_ro becomes very slow with KASAN (lots of PGDs) > > > > I have some vague memory that there was some debug double checking > > that pages are indeed read-only and that debug check was slow, but it > > was always executed without rodata=n. > > Sounds like debug_checkwx() which is disabled by turning off > CONFIG_DEBUG_WX. > > You could either disable it in your .configs or, provided there's even > such an option, disable KASAN checking around it until that one-time > boot test completes and then reenable KASAN.
Thanks! I've prepared a change that removes rodata=n: https://github.com/google/syzkaller/pull/2155 I think we will be able to indirectly evaluate if it helps or not over some period of time based on occurrence of any new similar crashes.
