Hi again, Wei, On Fri, Jun 22, 2018 at 09:18:27PM +0800, Wei Xu wrote: > On 2018/6/22 19:16, Will Deacon wrote: > >On Fri, Jun 22, 2018 at 06:45:15PM +0800, Wei Xu wrote: > >>On 2018/6/22 17:23, Will Deacon wrote: > >>>Perhaps just writing back the table entries is enough to cause the issue, > >>>although I really can't understand why that would be the case. Can you try > >>>the diff below (without my previous change), please? > >>Thanks! > >>But it does not resolve the issue(only apply this patch based on 4.17.0). > >Thanks, that's a useful data point. It means that it still crashes even if > >we write back the same table entries, so it's the fact that we're writing > >them at all which causes the problem, not the value that we write. > > > >Whilst looking at the code, we noticed a missing DMB. On the off-chance > >that it helps, can you try this instead please? > Thanks! > Only apply below patch based on 4.17.0, we still got the crash.
Oh well, it was worth a shot (and that's still a fix worth having). Please can you provide the complete disassembly for kpti_install_ng_mappings() (I'm referring to the C function in cpufeature.c) along with a corresponding crash log so that we can correlate the instruction stream with the crash? Thanks, Will