Just to clarify things.
Lots of processes die from illegal op traps.. gcc, bash, make, etc... but
the instruction is ALWAYS opcode 0x55 and is part of a subroutine preamble
in every case.. You are correct... 0x55 should not generate a trap.
Bad cpu? Hmmm, Tom has 6 different CPU's ( all p4 xeons ), on three
systems, that have this EXACT same problem.
and why does this require the system to be running smp?
- jim
Kurt Garloff <kurt@garloff.de>@vger.kernel.org on 03/20/2002 03:26:10 PM
Sent by: linux-kernel-owner@vger.kernel.org
To: Tom Epperly <tepperly@llnl.gov>
cc: Linux kernel list <linux-kernel@vger.kernel.org>
Subject: Re: Bad Illegal instruction traps on dual-Xeon (p4) Linux Dell
box
On Wed, Mar 20, 2002 at 01:35:30PM -0800, Tom Epperly wrote:
> The kernel log showed me that various standard programs such as
> /bin/sh are generating bogus illegal instruction traps on a legal
> opcode (0x55) as part of a standard function preamble. After receiving
> an illegal instruction trap on opcode (0x55), the modified kernel does
> a wbinvd() to flush the cache and a __flush_tlb() to flush the TLB
> and then retries the "illegal" opcode. The retry produces a second
> illegal instruction trap on the same legal opcode (0x55). Information
> from /var/log/messages is shown below.
The CPU is what triggers the exception.
So this sounds like a defect (or overheated) CPU to me.
OTOH, the kernel logs "invalid operand". Could you run ksymoops to get a
disassembly?
AFAICS, its a push %ebp instruction, which should not be illegal. So either
your stack is overflowing or my suspicion with the defect CPU is
applicable.
Regards,
-- Kurt Garloff <kurt@garloff.de> [Eindhoven, NL] Physics: Plasma simulations <K.Garloff@Phys.TUE.NL> [TU Eindhoven, NL] Linux: SCSI, Security <garloff@suse.de> [SuSE Nuernberg, DE] (See mail header or public key servers for PGP2 and GPG public keys.)
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