Re: [PATCH v3 3/3] sched, x86: Check that we're on the right stack in schedule and __might_sleep

[Andi Kleen]

On Wed, Nov 19, 2014 at 10:40:10AM -0800, Linus Torvalds wrote:
> On Tue, Nov 18, 2014 at 3:15 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:
> > On x86, sleeping while on an IST or irq stack has a surprisingly
> > good chance of working, but it can also fail dramatically.  Add an
> > arch hook to allow schedule and __might_sleep to catch sleeping on
> > the wrong stack.
> 
> Why doesn't the normal in_interrupt() test catch this?

The exception handlers which use the IST stacks don't necessarily 
set irq count. Maybe they should.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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