Re: 16k or 64k PAGE_SIZE and "illegal instruction" (signal -4) errors

[Joshua Kinard <kumba@gentoo.org>]

On 08/26/2014 08:03, Ralf Baechle wrote:
> On Tue, Aug 26, 2014 at 07:06:56AM -0400, Joshua Kinard wrote:
> 
>> o32 userland is the primary on both systems.  However, the last SIGILL was
>> under the 64k PAGE_SIZE kernel inside of an n32 chroot compiling the 'boost'
>> package on the Octane, which I restarted that and it's not complained since.
>>  Also got SIGILL on the 16k PAGE_SIZE kernel when I booted 16k PAGE_SIZE the
>> first time and ran 'ps'.  Subsequent runs of 'ps' didn't reproduce the
>> error.  Also saw SIGILLs in the bootlog of the 16k PAGE_SIZE kernel when
>> "rm" was ran once (couldn't reproduce) and when mdadm tried to put one of
>> the arrays back together.  Subsequent runs using similar argument lines
>> don't reproduce once I got to a root shell.
>>
>> Being it's a Gentoo install...the o32 userland is pretty fresh.  Especially
>> on the Octane, where I literally rebuilt the old userland over 2-3 times
>> just to make sure all the old 5-year cruft was gone.  The n32 userland
>> chroot is brand-spanking new.  gcc-4.7.x only for now on both, because of
>> PR61538 in gcc.  Latest binutils.
>>
>> The O2 is chugging away happily so far in updating a bunch of packages.  So
>> I am leaning towards this being another quirk I have to hunt down in the
>> Octane's code again.  There isn't much in the Octane-specific code that
>> deals with memory, though -- it seems the higher-level MIPS memory code
>> handles most things just fine.
> 
> Can you enable core dumps?  I'm wondering about the EPC of the crashed
> process.  If it's at a function entry or the beginning of a page that
> might indicate there is an issue with flushing caches after the containing
> page got loaded.  Also interesting to know if this possibly happened in a
> signal trampoline or VDSO.
> 
> These are just the usual suspects - nothing indicates this case is actually
> related.

(Missed the reply all on the last one)

Enabled coredumps and got the 'shash' program to fail a second time (first
program to do so)...so I'll rebuild that with debugging symbols and try to
trip it up again later on.

Is a core file from a binary w/o debugging of any value?

-- 
Joshua Kinard
Gentoo/MIPS
kumba@gentoo.org
4096R/D25D95E3 2011-03-28

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