Re: [patch 2.6.13-rc6] i386: semaphore ownership tracking

From: Chuck Ebbert
Date: Sat Aug 20 2005 - 02:11:43 EST


On Fri, 19 Aug 2005 at 20:02:27 -0700, Andrew Morton wrote:

> Chuck Ebbert <76306.1226@xxxxxxxxxxxxxx> wrote:
> >
> > This patch enables tracking semaphore ownership.
>
> Why? I can't think of any bug in recent years which needed this..

It might be useful in new driver development. OTOH it is really ugly
even if it's a small patch.

I did get an education from it, though. The usb-storage threads on my
system were sleeping on semaphores they already owned, making me wonder if
my patch really worked. It turns out that code in scsiglue.c does an up()
to wake them without ever acquiring the semaphore.

__
Chuck
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