----- Original Message -----
> Hi Dave,
>
> On Sat, Apr 18, 2020 at 2:08 PM Dave Anderson <ander...@redhat.com> wrote:
> >
> >
> >
> > ----- Original Message -----
> > > Hi Dave,
> > >
> > > Noticed that raw ramdumps of 5.4 kernel aren't working with crash tip.
> > > With the patches attached, I could get it working. Please take a look.
> > >
> > > Thanks,
> > > Vinayak
> > >
> >
> > Hi Vinayak,
> >
> > A couple quick questions come to mind...
> >
> > First, I haven't checked all possible READMEM plugins, but for example, if
> > this
> > function is run on a live system, the -1 file descriptor would cause the
> > READMEM()
> > call to fail:
>
>
> I changed it like this and it works for ramdump. I don't actually have
> a live setup to try this. Let me try
> to set up one.
>
> diff --git a/arm64.c b/arm64.c
> index 04efc13..fce3f8e 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -981,7 +981,7 @@ arm64_calc_physvirt_offset(void)
>
> if ((sp = kernel_symbol_search("physvirt_offset")) &&
> machdep->machspec->kimage_voffset) {
> - if (READMEM(-1, &physvirt_offset, sizeof(physvirt_offset),
> + if (READMEM(pc->mfd, &physvirt_offset,
> sizeof(physvirt_offset),
> sp->value, sp->value -
> machdep->machspec->kimage_voffset) > 0) {
> ms->physvirt_offset = physvirt_offset;
>
>
> >
> > static void
> > +arm64_calc_physvirt_offset(void)
> > +{
> > + struct machine_specific *ms = machdep->machspec;
> > + ulong physvirt_offset;
> > + struct syment *sp;
> > +
> > + ms->physvirt_offset = ms->phys_offset - ms->page_offset;
> > +
> > + if ((sp = kernel_symbol_search("physvirt_offset")) &&
> > + machdep->machspec->kimage_voffset) {
> > + if (READMEM(-1, &physvirt_offset, sizeof(physvirt_offset),
> > + sp->value, sp->value -
> > + machdep->machspec->kimage_voffset) > 0) {
> > + ms->physvirt_offset = physvirt_offset;
> > + }
> > + }
> > +
> > + if (CRASHDEBUG(1))
> > + fprintf(fp, "using %lx as physvirt_offset\n",
> > ms->physvirt_offset);
> > +}
> >
> > And here -- are you missing some brackets? (run "make warn")
> >
>
> I did try "make warn" and it does not show any issues.Am I missing something?
I saw on a system provisioned with Fedora's latest and greatest gcc version.
I don't have the system available any more, but the warning message picked up
on the fact that your second if statement "was not guarded" by the if statement
above it.
>
> > But regardless of that, why are you setting it back to 48 if it's greater
> > than 48?
> >
>
>
> I did that because machspec->CONFIG_ARM64_VA_BITS is used for calculation of
> vmemmap size. In kernel vmemmap size is calculated using VA_BITS_MIN and it is
> defined like this
>
> #if VA_BITS > 48
> #define VA_BITS_MIN (48)
> #else
> #define VA_BITS_MIN (VA_BITS)
> #endif
>
> But I realize now that its not the right thing to do, because
> machspec->CONFIG_ARM64_VA_BITS
> is later used in arm64_calc_VA_BITS to verify machspec->VA_BITS. So
> what about this ?
>
> diff --git a/arm64.c b/arm64.c
> index 04efc13..a35a30e 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -4023,8 +4023,6 @@ arm64_calc_virtual_memory_ranges(void)
> if ((ret = get_kernel_config("CONFIG_ARM64_VA_BITS",
> &string)) == IKCONFIG_STR)
> machdep->machspec->CONFIG_ARM64_VA_BITS =
> atol(string);
> - if (machdep->machspec->CONFIG_ARM64_VA_BITS >
> 48)
> -
> machdep->machspec->CONFIG_ARM64_VA_BITS = 48;
> }
> }
>
> @@ -4049,7 +4047,12 @@ arm64_calc_virtual_memory_ranges(void)
> #define STRUCT_PAGE_MAX_SHIFT 6
>
> if (ms->VA_BITS_ACTUAL) {
> - vmemmap_size = (1UL) << (ms->CONFIG_ARM64_VA_BITS -
> machdep->pageshift - 1 + STRUCT_PAGE_MAX_SHIFT);
> + ulong va_bits_min = 48;
> +
> + if (machdep->machspec->CONFIG_ARM64_VA_BITS < 48)
> + va_bits_min = ms->CONFIG_ARM64_VA_BITS;
> +
> + vmemmap_size = (1UL) << (va_bits_min - machdep->pageshift - 1
> + STRUCT_PAGE_MAX_SHIFT);
> vmalloc_end = (- PUD_SIZE - vmemmap_size - KILOBYTES(64));
> vmemmap_start = (-vmemmap_size);
> ms->vmalloc_end = vmalloc_end - 1;
>
Yeah, that looks reasonable. But what about the parallel discussion re:
vmemmap_start?
https://www.redhat.com/archives/crash-utility/2020-April/msg00064.html
Can you send in an updated patch set with all fixes applied?
Thanks,
Dave
Shouldn't it be
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