Messages in this thread | | | Date | Wed, 20 Jun 2018 17:28:45 +0100 | From | Will Deacon <> | Subject | Re: KVM guest sometimes failed to boot because of kernel stack overflow if KPTI is enabled on a hisilicon ARM64 platform. |
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On Thu, Jun 21, 2018 at 12:25:05AM +0800, Wei Xu wrote: > Hi James, > > On 2018/6/20 23:54, James Morse wrote: > >Hi Wei, > > > >On 20/06/18 16:52, Wei Xu wrote: > >>On 2018/6/20 22:42, Will Deacon wrote: > >>>Hmm, I wonder if this is at all related to RAS, since we've just enabled > >>>that and if we take a fault whilst rewriting swapper then we're going to > >>>get stuck. What happens if you set CONFIG_ARM64_RAS_EXTN=n in the guest? > >>I will try it now. > >It's not just the Kconfig symbol, could you also revert: > > > >f751daa4f9d3 ("arm64: Unconditionally enable IESB on exception entry/return for > >firmware-first") > > > > > >(reverts and build cleanly on 4.17) > > Thanks to point out this! > I have disabled CONFIG_ARM64_RAS_EXTN and reverted that commit. > But I still got the stack overflow issue sometimes. > Do you have more hint?
[...]
> [ 0.076797] pstate: 604003c5 (nZCv DAIF +PAN -UAO) > [ 0.081727] pc : el1_sync+0x0/0xb0 > [ 0.085217] lr : kpti_install_ng_mappings+0x120/0x214
Please run:
$ ./scripts/faddr2line vmlinux kpti_install_ng_mappings+0x120/0x214
as the GDB output wasn't helpful (it only showed local variable declarations?!).
Will
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