From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: 2.6.3 Heisenbug in unwind.c
Date: Tue, 24 Feb 2004 14:29:45 +0000 [thread overview]
Message-ID: <16443.24537.894757.554578@napali.hpl.hp.com> (raw)
In-Reply-To: <2654.1077624337@ocs3.ocs.com.au>
>>>>> On Tue, 24 Feb 2004 23:05:37 +1100, Keith Owens <kaos@sgi.com> said:
Keith> I am seeing a Heisenbug in the 2.6.3 kernel unwind code. The
Keith> symptoms are that the backtrace terminates early, usually
Keith> failing to unwind past an interrupt frame.
I haven't seen that in quite some time.
Keith> Andreas, this _may_ be what you are seeing.
Keith> Changing the config options (sn2->dig) makes backtrace work
Keith> again. Turning on UNW_DEBUG to debug the unwinder makes
Keith> backtrace work again :(. Adding 30 dummy functions (which
Keith> only call printk and are never called themselves) to unwind.c
Keith> makes the backtrace work again.
Keith> That last one really worries me. All it does is shift the
Keith> position of the real unwind code within the kernel without
Keith> changing the unwind code itself. Looks like an uninitialised
Keith> pointer somewhere.
Keith> gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-24) GNU
Keith> assembler version 2.14.90.0.4 (ia64-unknown-linux-gnu) using
Keith> BFD version 2.14.90.0.4 20030523
It doesn't sound like a timing-related bug though, which is good news.
If you could reproduce the problem with Ski, that would almosts certainly
make it possible to root-cause it relatively quickly.
It might also be worthwhile to see if gcc 3.3.3 or 3.4 makes any difference.
--david
next prev parent reply other threads:[~2004-02-24 14:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-24 12:05 2.6.3 Heisenbug in unwind.c Keith Owens
2004-02-24 14:29 ` David Mosberger [this message]
2004-03-10 5:27 ` Keith Owens
2004-03-11 7:56 ` David Mosberger
2004-03-11 8:14 ` Keith Owens
2004-03-15 6:52 ` Keith Owens
2004-03-16 6:22 ` Keith Owens
2004-03-16 10:42 ` Keith Owens
2004-03-17 22:46 ` Keith Owens
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