Subject: race condition in APM support?
To: None <firstname.lastname@example.org>
From: Steven M. Bellovin <email@example.com>
Date: 06/14/2006 11:07:39
I suspect that there's a race condition in the APM support, but I'm not
certain, and don't really know how to track it down.
Here's the situation. I have a Thinkpad T42 with two batteries, one of
which is very bad. (A replacement is on order.) Three times in the last
week, while I was running on battery with high power drain (wireless
networking, high CPU use, and intensive disk activity), the machine has
turned itself off. Looking at the battery level after rebooting, I
believe that the bad battery had hit 0%.
I suspect that what's happening is that some APM events are coming in very
close together, and that that's confusing something in the APM support. A
race condition is the obvious guess, though I have no evidence to support
it. Neither apmd nor sysutils/asapm seem to have any defaults to power
off the machine. The BIOS will, when the battery power is about 0%, but
that would apply to the total battery, not one battery. I can't, of
course, rule out a BIOS bug, and I'll certainly be checking the Lenovo web
Has anyone seen anything like this? Any suggestions on tracking it down?
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb