[Crash-utility] arm64: doesn't work for kernel v5.4?

[AKASHI Takahiro]

On Tue, Oct 08, 2019 at 04:55:48PM -0400, Dave Anderson wrote:
> 
> > ----- Original Message -----
> > > Hi Dave,
> > > 
> > > I tried to use crash v7.2.7 with kernel v5.4-rc1 on arm64.
> > > 
> > > 1. VA_BITS_ACTUAL is missing in vmcoreinfo.
> > >    Does anyone work on fixing it on kernel side?
> > >    (just adding one or two lines though)
> > > 
> > > 2. With a tweak above, I still fail to run crash with vmcore
> > >    seeing the following errors;
> > >    (I didn't dig into details)
> > > 
> > >    crash-arm64: invalid kernel virtual address: ffff800010c689a8  type: "kernel_config_data"
> > >    WARNING: cannot read kernel_config_data
> > >    crash-arm64: invalid kernel virtual address: ffff80001177a160  type: "possible"
> > >    WARNING: cannot read cpu_possible_map
> > >    crash-arm64: invalid kernel virtual address: ffff80001177a140  type: "present"
> > >    WARNING: cannot read cpu_present_map
> > >    crash-arm64: invalid kernel virtual address: ffff80001177a120  type: "online"
> > >    WARNING: cannot read cpu_online_map 
> > >    crash-arm64: invalid kernel virtual address: ffff80001177a188  type: "active" 
> > >    WARNING: cannot read cpu_active_map
> > >    crash-arm64: invalid kernel virtual address: ffff80001196afe0  type: "shadow_timekeeper xtime_sec"
> > >    crash-arm64: invalid kernel virtual address: ffff800011782b3c  type: "init_uts_ns"
> > >    WARNING: invalid linux_banner pointer: ffff800010c500e8
> > >    crash: vmlinux.1003 and vmcore.1003 do not match!
> > > 
> > > Have you noticed this issue?
> > 
> > I have been waiting for our internal 5.4-rc1 based ARK kernel to be built,
> > and it looks like it should be available soon.  But I did not expect crash
> > to work on arm64 in 5.4.    
> > 
> > I put in a bunch of 52-bit support into the crash utility last spring, but 
> > it was based upon an early proposed patch-set from Steve Capper that Chris
> > von Recklinghausen backported to our 4.18.0-80.el8 kernel at the time.
> > I believe Chris may have added the VA_BITS_ACTUAL vmcoreinfo entry (?),
> > and I'm presuming there will be other VM-related things that are 
> > different from that original kernel patch.
> > 
> > Thanks,
> >   Dave
> 
> I still haven't got a 5.4-rc1 kernel to test with, but Chris Von Recklinghausen
> has backported the latest upstream 52-bit patch-set to a 4.18-based kernel.  
> However, it did require one additional patch needed for crash to run live 
> on /proc/kcore, which he posted on the arm list today:
> 
>   [PATCH] arm64: remove arm64 definitions of kc_vaddr_to_offset and kc_offset_to_vaddr.
>   http://lists.infradead.org/pipermail/linux-arm-kernel/2019-October/685109.html
> 
> With his patch-set (including the above), crash-7.2.7 comes up unmodified on 
> a live system -- albeit one which downgrades from 52 bits to 48 bits.  Chris is 
> going to test crash running live on a 52 bit simulator tomorrow.

I may misunderstand something, but even after applying this patch,
nothing has changed, at least, against /proc/vmcore. (I see the same errors.)

Thanks,
-Takahiro Akashi


> Dave
> 
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