Re: crypto: ablk_decrypt causes BUG in scatterwalk

From	Dmitry Vyukov <dvyukov@google.com>
Newsgroups	linux.kernel
Subject	Re: crypto: ablk_decrypt causes BUG in scatterwalk
Date	2016-01-12 17:30 +0100
Message-ID	<qQ9Zw-3q9-5@gated-at.bofh.it> (permalink)
References	<qQ3r4-7nB-31@gated-at.bofh.it> <qQ71F-1nL-17@gated-at.bofh.it> <qQ7bj-1rC-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, Jan 12, 2016 at 2:23 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
> On Tue, Jan 12, 2016 at 2:16 PM, Herbert Xu <herbert@gondor.apana.org.au> 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:
https://gist.githubusercontent.com/dvyukov/94aed45494edf1dff0a8/raw/a31f439fdcdd8a8905235a9bce6e5863ca8ccf68/gistfile1.txt

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

It triggers the BUG within seconds for me.

Thread

crypto: ablk_decrypt causes BUG in scatterwalk Dmitry Vyukov <dvyukov@google.com> - 2016-01-12 10:40 +0100
  Re: crypto: ablk_decrypt causes BUG in scatterwalk Herbert Xu <herbert@gondor.apana.org.au> - 2016-01-12 14:20 +0100
    Re: crypto: ablk_decrypt causes BUG in scatterwalk Dmitry Vyukov <dvyukov@google.com> - 2016-01-12 14:30 +0100
      Re: crypto: ablk_decrypt causes BUG in scatterwalk Dmitry Vyukov <dvyukov@google.com> - 2016-01-12 17:30 +0100
        Re: crypto: ablk_decrypt causes BUG in scatterwalk Dmitry Vyukov <dvyukov@google.com> - 2016-01-12 18:10 +0100
          Re: crypto: ablk_decrypt causes BUG in scatterwalk Dmitry Vyukov <dvyukov@google.com> - 2016-01-12 19:20 +0100

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