Date: Tue, 8 Jan 2008 20:10:42 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Valdis.Kletnieks@vt.edu
Cc: Matthew Wilcox <matthew@wil.cx>, Willy Tarreau <w@1wt.eu>,
       Adrian Bunk <bunk@kernel.org>,
       James Bottomley <James.Bottomley@HansenPartnership.com>,
       Ingo Molnar <mingo@elte.hu>, Peter Osterlund <petero2@telia.com>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org, Al Viro <viro@ftp.linux.org.uk>
Subject: Re: [patch] scsi: revert "[SCSI] Get rid of scsi_cmnd->done"
Message-Id: <20080108201042.03c3aead.akpm@linux-foundation.org>
In-Reply-To: <8336.1199851267@turing-police.cc.vt.edu>
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On Tue, 08 Jan 2008 23:01:07 -0500 Valdis.Kletnieks@vt.edu wrote:

> On Mon, 07 Jan 2008 16:19:30 MST, Matthew Wilcox said:
> > On Mon, Jan 07, 2008 at 06:04:25PM -0500, Valdis.Kletnieks@vt.edu wrote:
> > > Theoretically, at least.  Sometimes, in the real world, other constraints
> > > enter into it...
> > 
> > So you're saying that you can't find reliable ways to reproduce problems
> > on demand?  Those are some of the lower quality bug reports, so I don't
> > think we're losing much by having you not report them.
> 
> I'm sure that *everybody* on this list would *love* to know how you find
> a reliable way to reproduce all the bugs that start off with "after X days of
> uptime".   But when you're chasing what might be a race condition with a
> very small timing hole, you may need an event to happen several million times
> before the accumulated chance of hitting it becomes appreciable.
> 

I must say that the number of bugs which actually go away when the user
stops using nvidia/fglrx/ndiswrapper/etc is a small minority.

And you can usually tell beforehand too: if the user reports bad_page
warnings or pte table scroggage or whatever and they're using nvidia I just
hit 'd'.  But people who think that removing the nvidia driver will
magically fix that khubd-got-stuck-in-D-state bug are urinating up an
incline.


Facts:

- lots of people use nvidia/etc

- most bugs they report aren't caused by nvidia/etc

- we need lots of testers

draw you own conclusions.
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