Begin forwarded message:
From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: February 20, 2008 10:50:01 AM EST
To: dm-devel@xxxxxxxxxx
Subject: 2.6.25-rc1 patch prevents booting on LVM-based devices
Hello-
I've got a Fedora 8 x86 test system that uses LVM volumes for all
it's file systems except /boot. After commit bdc80787, 2.6.24+
doesn't boot on this system -- the LVM volume scan during start-up
can no longer find any physical volumes on the system.
I'm not sure whether this is an LVM issue, or something else is
breaking during system init which prevents the LVM scan from
working. I need some help troubleshooting the problem.
Interestingly, if I build a non-tickless kernel, the problem goes away.
bdc80787 is:
commit bdc807871d58285737d50dc6163d0feb72cb0dc2
Author: H. Peter Anvin <hpa@xxxxxxxxx>
Date: Fri Feb 8 04:21:26 2008 -0800
avoid overflows in kernel/time.c
When the conversion factor between jiffies and milli- or
microseconds is
not a single multiply or divide, as for the case of HZ == 300,
we currently
do a multiply followed by a divide. The intervening result,
however, is
subject to overflows, especially since the fraction is not
simplified (for
HZ == 300, we multiply by 300 and divide by 1000).
This is exposed to the user when passing a large timeout to poll
(), for
example.
This patch replaces the multiply-divide with a reciprocal
multiplication on
32-bit platforms. When the input is an unsigned long, there is
no portable
way to do this on 64-bit platforms there is no portable way to
do this
since it requires a 128-bit intermediate result (which gcc does
support on
64-bit platforms but may generate libgcc calls, e.g. on 64-bit
s390), but
since the output is a 32-bit integer in the cases affected,
just simplify
the multiply-divide (*3/10 instead of *300/1000).
and so on...
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com
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