RE: [PATCH v5 06/13] lockdep: Implement crossrelease feature

From: byungchul.park
Date: Thu Mar 02 2017 - 01:15:43 EST


> -----Original Message-----
> From: Matthew Wilcox [mailto:willy@xxxxxxxxxxxxx]
> Sent: Thursday, March 02, 2017 1:20 PM
> To: Peter Zijlstra
> Cc: Byungchul Park; mingo@xxxxxxxxxx; tglx@xxxxxxxxxxxxx;
> walken@xxxxxxxxxx; boqun.feng@xxxxxxxxx; kirill@xxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; iamjoonsoo.kim@xxxxxxx;
> akpm@xxxxxxxxxxxxxxxxxxxx; npiggin@xxxxxxxxx
> Subject: Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature
>
> On Tue, Feb 28, 2017 at 07:15:47PM +0100, Peter Zijlstra wrote:
> > (And we should not be returning to userspace with locks held anyway --
> > lockdep already has a check for that).
>
> Don't we return to userspace with page locks held, eg during async
> directio?

Hello,

I think that the check when returning to user with crosslocks held
should be an exception. Don't you think so?

Thanks,
Byungchul