Re: crypto: ablk_decrypt causes BUG in scatterwalk

From: Dmitry Vyukov
Date: Tue Jan 12 2016 - 11:28:19 EST

On Tue, Jan 12, 2016 at 2:23 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> On Tue, Jan 12, 2016 at 2:16 PM, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote:
>> On Tue, Jan 12, 2016 at 10:27:44AM +0100, Dmitry Vyukov wrote:
>>> Hello,
>>> The following program cause BUG in scatterwalk:
>> Weird, I can't reproduce the crash. Can you perhaps convert this to
>> a non-racy reproduction, possibly by using strace to find the order
>> of execution that leads to the crash?
> Concurrent execution seems to be important to reproduce the crash. I
> wasn't able to reproduce it in single-threaded mode.
> Try to run it in a tight parallel loop for some time.

I've extracted another reproducer:

I don't know whether there is a simpler way to run a reproducer in a
tight parallel loop, but I use:
$ go get
$ GOPATH/bin/stress -p 16 ./a.out

It triggers the BUG within seconds for me.