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Date: Mon, 9 May 2016 13:37:37 +0200
Message-ID: <CA+icZUWx31BhOCQjKMpPf7iF7T0dMwMpPKz9MVayNTzZX4mU3g@mail.gmail.com>
Subject: Re: [Linux-v4.6-rc1] ext4: WARNING: CPU: 2 PID: 2692 at
 kernel/locking/lockdep.c:2017 __lock_acquire+0x180e/0x2260
From: Sedat Dilek <sedat.dilek@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
        Alfredo Alvarez Fernandez <alfredoalvarezfernandez@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On 4/4/16, Peter Zijlstra <peterz@infradead.org> wrote:
> On Mon, Apr 04, 2016 at 05:31:40PM +0200, Sedat Dilek wrote:
>> > +/* https://en.wikipedia.org/wiki/Xorshift#xorshift.2A */
>> > +#define UINT64_C(x) x##ULL
>> > +static inline u64 xorshift64star(u64 x)
>> > +{
>> > +       x ^= x >> 12; // a
>> > +       x ^= x << 25; // b
>> > +       x ^= x >> 27; // c
>> > +       return x * UINT64_C(2685821657736338717);
>> > +}
>
>> Will you push that also to peterz/queue.git#locking/urgent?
>
> Only after I've had a play and observed it making any difference; Dmitry
> supposedly has a reproducer, but I've not yet had a moment to try.
>

Hi Peter,

any news on that stuff?
How can someone test this?
How did Dmitry reproduce?

Regards,
- Sedat -