[Crash-utility] [PATCH 0/1] arm64: Fix missing offset for modules_vaddr with aarch64 guest dump

[Masayoshi Mizuma]

On Mon, Jan 27, 2020 at 09:56:53AM -0500, Dave Anderson wrote:
> 
> 
> ----- Original Message -----
> > From: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>
> > 
> > Fix for aarch64 with Linux v5.0 and later kernels that
> > contains commit 91fc957c9b1d ("arm64/bpf: don't allocate
> > BPF JIT programs in module memory") and the memory dump
> > is captured by virsh dump.
> > 
> > Note: Another two issues remain for the memory dump captured by
> > virsh dump with aarch64.
> 
> I'm confused -- the vmcoreinfo data has been passed to the KVM host
> for the virsh dump for quite some time now.  Is it not passed back
> to the host on aarch64?

The vmcore_data shows that vmcoreinfo size is 0, so I think vmcoreinfo
isn't captured by virsh dump.
Am I missing something...?

./crash -d1 vmlinux-v5.4 dump.v5.4
...
vmcore_data:
                  flags: c0 (KDUMP_LOCAL|KDUMP_ELF64)
                   ndfd: 3
                    ofp: ffffa5e81588
            header_size: 30896
   num_pt_load_segments: 1
     pt_load_segment[0]:
            file_offset: 78b0
             phys_start: 40000000
               phys_end: 260000000
              zero_fill: 0
             elf_header: 2ed6d4e0
                  elf32: 0
                notes32: 0
                 load32: 0
                  elf64: 2ed6d4e0
                notes64: 2ed6d520
                 load64: 2ed6d558
               sect0_64: 0
            nt_prstatus: 2ed6d590
            nt_prpsinfo: 0
          nt_taskstruct: 0
            task_struct: 0
             arch_data1: (unused)
             arch_data2: (unused)
           switch_stack: 0
              page_size: 0
         xen_kdump_data: (unused)
     num_prstatus_notes: 32
         num_qemu_notes: 0
             vmcoreinfo: 0
        size_vmcoreinfo: 0
     nt_prstatus_percpu:
        000000002ed6d590 000000002ed6d950 000000002ed6dd10 000000002ed6e0d0
        000000002ed6e490 000000002ed6e850 000000002ed6ec10 000000002ed6efd0
        000000002ed6f390 000000002ed6f750 000000002ed6fb10 000000002ed6fed0
        000000002ed70290 000000002ed70650 000000002ed70a10 000000002ed70dd0
        000000002ed71190 000000002ed71550 000000002ed71910 000000002ed71cd0 
        000000002ed72090 000000002ed72450 000000002ed72810 000000002ed72bd0 
        000000002ed72f90 000000002ed73350 000000002ed73710 000000002ed73ad0 
        000000002ed73e90 000000002ed74250 000000002ed74610 000000002ed749d0 
         nt_qemu_percpu: 
       backup_src_start: 0
        backup_src_size: 0
          backup_offset: 0
...

Thanks,
Masa

> 
> Dave
> 
>   I
> > 
> > 1. KASLR
> >    crash doesn't work in case KASLR is enabled on the guest.
> >    That is because the memory dump doesn't have vmcoreinfo, so we
> >    cannot get the relocation position.
> >    I suppose we need to implement calc_kaslr_offset() for aarch64.
> >    nokaslr with the guest kernel parameter is a workaround.
> > 
> > 2. VA_BITS
> >    crash doesn't work in case the guest kernel is v5.4 and later.
> >    That is because the memory dump doesn't have vmcoreinfo, so we
> >    cannot get vabits_actual.
> >    I think there's no workaround so far...
> > 
> > Masayoshi Mizuma (1):
> >   arm64: Fix missing offset for modules_vaddr with aarch64 guest dump
> > 
> >  arm64.c | 2 ++
> >  defs.h  | 3 +++
> >  2 files changed, 5 insertions(+)
> > 
> > --
> > 2.18.1
> > 
> > 
> > --
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> > Crash-utility at redhat.com
> > https://www.redhat.com/mailman/listinfo/crash-utility
> > 
> 
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