lkml.org 
[lkml]   [2017]   [Jul]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v7 06/16] lockdep: Detect and handle hist_lock ring buffer overwrite
On Thu, Jul 13, 2017 at 8:12 PM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Thu, Jul 13, 2017 at 12:29:05PM +0200, Peter Zijlstra wrote:
>> On Thu, Jul 13, 2017 at 07:09:53PM +0900, Byungchul Park wrote:
>> > On Thu, Jul 13, 2017 at 11:50:52AM +0200, Peter Zijlstra wrote:
>> > > wait_for_completion(&C);
>> > > atomic_inc_return();
>> > >
>> > > mutex_lock(A1);
>> > > mutex_unlock(A1);
>> > >
>> > >
>> > > <IRQ>
>> > > spin_lock(B1);
>> > > spin_unlock(B1);
>> > >
>> > > ...
>> > >
>> > > spin_lock(B64);
>> > > spin_unlock(B64);
>> > > </IRQ>
>> > >
>> > >
>
> Also consider the alternative:
>
> <IRQ>
> spin_lock(D);
> spin_unlock(D);
>
> complete(&C);
> </IRQ>
>
> in which case the context test will also not work.

Context tests are done on xhlock with the release context, _not_
acquisition context. For example, spin_lock(D) and complete(&C) are
in the same context, so the test would pass in this example.

So it works.


--
Thanks,
Byungchul

\
 
 \ /
  Last update: 2017-07-13 13:24    [W:0.217 / U:0.352 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site