[Crash-utility] [PATCH] Improve error handling when architecture doesn't match

[Dave Anderson]

 > Bernhard Walle wrote:
 > > Dave Anderson wrote:
 > >
 > > Actually this patch has just turned up different issues
 > > that have to be handled, because the e_type and e_phnum
 > > get deferred until after the e_machine and endianness
 > > are checked.
 > >
 > > Among them the fact that an i386 xen guest core file
 > > taken by an x86_64 host has the e_machine type set
 > > to x86_64 (don't ask me why they did that...), and has
 > > an e_phnum of 0.  Anyway, that requires the e_phnum
 > > to be checked *before* the machine type and endianness.
 > >
 > > And another, since the e_type doesn't get checked
 > > until *after* the machine type and endianness,
 > > it allows the vmlinux file (ET_EXEC) to get passed
 > > through, which can generate a bogus error message
 > > about the vmlinux file!
 > >
 > > And there's probably others...
 > >
 > > There was a method to my madness in the way it's written
 > > now.  I'm going to have to spend some more time with
 > > this because I don't want to introduce false alarms
 > > or print error messages that don't make any sense...
 >
 > *Arrrg*, sorry for not taking all this into account. I only tested
 > with a few Kdump dumps from different architectures, but not with Xen
 > dumps.
 >
 > You're right, and I'll send a new patch that tries to handle all this.
 > But probably next year ...

No need -- I've got it all in place.  Prior to the generic "not a supported
file format" fatal error message, the following mismatches will be
explicitly reported:

   1. Machine type mismatches in netdump, kdump, diskdump and
      xendump ELF dumpfiles.
   2. Machine type mismatches in compressed diskdump and
      compressed kdump (via makedumpfile) dumpfiles.
   3. Machine type mismatches in vmlinux files.
   4. Endian mismatches in netdump, kdump, diskdump and
      xendump ELF core dumpfiles.
   5. Endian mismatches in vmlinux files.

This was long overdue -- thanks a lot for getting the ball rolling.

Dave