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

[Masayoshi Mizuma]

On Mon, Jan 27, 2020 at 10:17:51AM -0500, Dave Anderson wrote:
> 
> 
> ----- Original Message -----
> > 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...?
> 
> I'm not sure -- are you using "virsh dump --memory-only ..."?

Yes, I'm using --memory-only option like as:

virsh dump --crash --memory-only <Guest> <Dumpfile>

- Masa

> 
> Dave
> 
> 
> > 
> > ./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
> > > > 
> > > > 
> > > > --
> > > > Crash-utility mailing list
> > > > Crash-utility at redhat.com
> > > > https://www.redhat.com/mailman/listinfo/crash-utility
> > > > 
> > > 
> > > --
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> > > 
> > 
> > 
>