Re: [PATCH][2.6-mm] Fix 4G/4G X11/vm86 oops

From: Linus Torvalds <torvalds@osdl.org>
To: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Andrew Morton <akpm@osdl.org>, <jon@jon-foster.co.uk>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH][2.6-mm] Fix 4G/4G X11/vm86 oops
Date: Tue, 18 Nov 2003 23:24:04 -0800 (PST)	[thread overview]
Message-ID: <Pine.LNX.4.44.0311182310430.23026-100000@home.osdl.org> (raw)
In-Reply-To: <Pine.LNX.4.53.0311190147060.11537@montezuma.fsmlabs.com>

On Wed, 19 Nov 2003, Zwane Mwaikambo wrote:
> 
> I just tried the RH9 2.96 and it also triple faulted. Oh my.. The only 
> unique thing about this hardware compared ot the other stuff i have here 
> is that it's an AMD K6. Everything else is Intel.

Different TLB sizes (and organizations) etc can _easily_ matter, if the 
Intel one just happens to work because something stays in the TLB while 
the page table mapping is incorrect and keeps the system afloat.

Or - and in this case more likely - since the problem is fixed by running
a (complex) thing that trashes all over the DTLB/ITLB, it's more likely
that there might be a _missing_ TLB invalidate somewhere, and that the
Intel boxes stay up because they have a smaller TLB and the stale entry
gets flushed out early from them.

But you already tried a "flush_tlb_all()" which _should_ have flushed
absolutely everything, including global tables. I dunno. It could be
hitting a CPU bug too, of course. 

It would be interesting to hear if other K6 users see problems..

			Linus