Re: bio linked list corruption.

From: Dave Jones
Date: Thu Oct 20 2016 - 19:03:55 EST


On Thu, Oct 20, 2016 at 04:01:12PM -0700, Andy Lutomirski wrote:
> On Thu, Oct 20, 2016 at 3:50 PM, Dave Jones <davej@xxxxxxxxxxxxxxxxx> wrote:
> > On Tue, Oct 18, 2016 at 06:05:57PM -0700, Andy Lutomirski wrote:
> >
> > > One possible debugging approach would be to change:
> > >
> > > #define NR_CACHED_STACKS 2
> > >
> > > to
> > >
> > > #define NR_CACHED_STACKS 0
> > >
> > > in kernel/fork.c and to set CONFIG_DEBUG_PAGEALLOC=y. The latter will
> > > force an immediate TLB flush after vfree.
> >
> > I can give that idea some runtime, but it sounds like this a case where
> > we're trying to prove a negative, and that'll just run and run ? In which case I
> > might do this when I'm travelling on Sunday.
>
> The idea is that the stack will be free and unmapped immediately upon
> process exit if configured like this so that bogus stack accesses (by
> the CPU, not DMA) would OOPS immediately.

oh, misparsed. ok, I can definitely get behind that idea then.
I'll do that next.

Dave