Hi, Kazu
Thank you for the comment.
On Wed, Oct 5, 2022 at 5:11 PM HAGIO KAZUHITO(萩尾 一仁) <k-hagio...@nec.com>
wrote:

> Hi Lianbo,
>
> On 2022/10/05 11:22, Lianbo Jiang wrote:
> > Currently crash will fail and then exit, if the initialization of
> > the emergency stacks information fails. In real customer environments,
> > sometimes, a vmcore may be partially damaged, although such vmcores
> > are rare. For example:
> >
> >    # ./crash ../3.10.0-1127.18.2.el7.ppc64le/vmcore
> ../3.10.0-1127.18.2.el7.ppc64le/vmlinux  -s
> >    crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
> >    #
> >
> > Lets try to keep loading vmcore if such issues happen, so call
> > the readmem() with the RETURN_ON_ERROR instead of FAULT_ON_ERROR,
> > which allows the crash move on.
>
> Just to confirm, can I have the error messages printed with the patch
> for the vmcore?
>

Yes. Crash has the following error messages printed after applying this
patch:

# ./crash ../vmcore ../vmlinux -s
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: fc4  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 38  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 1000138  type: "paca->emergency_sp"
crash: invalid kernel virtual address: 100000040  type: "paca->emergency_sp"
...

Thanks.
Lianbo

Thanks,
> Kazu
>
> >
> > Reported-by: Dave Wysochanski <dwyso...@redhat.com>
> > Signed-off-by: Lianbo Jiang <liji...@redhat.com>
> > ---
> >   ppc64.c | 12 ++++++------
> >   1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/ppc64.c b/ppc64.c
> > index 4ea1f7c0c6f8..f94b402ec64d 100644
> > --- a/ppc64.c
> > +++ b/ppc64.c
> > @@ -1224,13 +1224,13 @@ ppc64_init_paca_info(void)
> >               ulong paca_loc;
> >
> >               readmem(symbol_value("paca_ptrs"), KVADDR, &paca_loc,
> sizeof(void *),
> > -                     "paca double pointer", FAULT_ON_ERROR);
> > +                     "paca double pointer", RETURN_ON_ERROR);
> >               readmem(paca_loc, KVADDR, paca_ptr, sizeof(void *) *
> kt->cpus,
> > -                     "paca pointers", FAULT_ON_ERROR);
> > +                     "paca pointers", RETURN_ON_ERROR);
> >       } else if (symbol_exists("paca") &&
> >                  (get_symbol_type("paca", NULL, NULL) == TYPE_CODE_PTR))
> {
> >               readmem(symbol_value("paca"), KVADDR, paca_ptr,
> sizeof(void *) * kt->cpus,
> > -                     "paca pointers", FAULT_ON_ERROR);
> > +                     "paca pointers", RETURN_ON_ERROR);
> >       } else {
> >               free(paca_ptr);
> >               return;
> > @@ -1245,7 +1245,7 @@ ppc64_init_paca_info(void)
> >               for (i = 0; i < kt->cpus; i++)
> >                       readmem(paca_ptr[i] + offset, KVADDR,
> &ms->emergency_sp[i],
> >                               sizeof(void *), "paca->emergency_sp",
> > -                             FAULT_ON_ERROR);
> > +                             RETURN_ON_ERROR);
> >       }
> >
> >       if (MEMBER_EXISTS("paca_struct", "nmi_emergency_sp")) {
> > @@ -1256,7 +1256,7 @@ ppc64_init_paca_info(void)
> >               for (i = 0; i < kt->cpus; i++)
> >                       readmem(paca_ptr[i] + offset, KVADDR,
> &ms->nmi_emergency_sp[i],
> >                               sizeof(void *), "paca->nmi_emergency_sp",
> > -                             FAULT_ON_ERROR);
> > +                             RETURN_ON_ERROR);
> >       }
> >
> >       if (MEMBER_EXISTS("paca_struct", "mc_emergency_sp")) {
> > @@ -1267,7 +1267,7 @@ ppc64_init_paca_info(void)
> >               for (i = 0; i < kt->cpus; i++)
> >                       readmem(paca_ptr[i] + offset, KVADDR,
> &ms->mc_emergency_sp[i],
> >                               sizeof(void *), "paca->mc_emergency_sp",
> > -                             FAULT_ON_ERROR);
> > +                             RETURN_ON_ERROR);
> >       }
> >
> >       free(paca_ptr);
--
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