On 03/07/17 at 06:53am, Pratyush Anand wrote:
> Hi Simon,
>
> On Wednesday 01 March 2017 12:43 PM, Dave Young wrote:
> > On 03/01/17 at 11:19am, Pratyush Anand wrote:
> > > Currently, all the p_paddr of PT_LOAD headers are assigned to 0, which
> > > is not correct and could be misleading, since 0 is a valid physical
> > > address.
> > >
> > > Upstream kernel commit "464920104bf7 /proc/kcore: update physical
> > > address for kcore ram and text" fixed it and now invalid PT_LOAD is
> > > assigned as -1.
> > >
> > > kexec/arch/i386/crashdump-x86.c:get_kernel_vaddr_and_size() uses kcore
> > > interface and so calls build_mem_phdrs() for kcore PT_LOAD headers.
> > >
> > > This patch fixes build_mem_phdrs() to check if p_paddr is invalid.
>
> Any comment on this?
Simon, ping, explain a bit about the background based on the patch log:
Although it is a kernel regression, the original p_addr = 0 assumption is
wrong, it should be fixed in kernel instead of keep it to avoid
kexec-tools breakage.
Since latest kernel already has the fix merged, kexec-tools will fail to
load crash kernel now.
Any opinion about this patch?
>
> > >
> > > Signed-off-by: Pratyush Anand <panand at redhat.com>
> > > ---
> > > kexec/kexec-elf.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/kexec/kexec-elf.c b/kexec/kexec-elf.c
> > > index 1d6320a2f0e6..be60bbd48486 100644
> > > --- a/kexec/kexec-elf.c
> > > +++ b/kexec/kexec-elf.c
> > > @@ -432,7 +432,8 @@ static int build_mem_phdrs(const char *buf, off_t len, struct mem_ehdr *ehdr,
> > > }
> > > return -1;
> > > }
> > > - if ((phdr->p_paddr + phdr->p_memsz) < phdr->p_paddr) {
> > > + if (phdr->p_paddr != (unsigned long long)-1 &&
> > > + (phdr->p_paddr + phdr->p_memsz) < phdr->p_paddr) {
> > > /* The memory address wraps */
> > > if (probe_debug) {
> > > fprintf(stderr, "ELF address wrap around\n");
> > > --
> > > 2.9.3
> > >
> >
> > Acked-by: Dave Young <dyoung at redhat.com>
> >
>
>
>
> ~Pratyush
>
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Thanks
Dave
