Re: crypto: ablk_decrypt causes BUG in scatterwalk

I can _not_ reproduce it on clean upstream tree, nor on
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6.git.
I probably messed up something with the unmerged fixes during my rebase.
Sorry.



On Tue, Jan 12, 2016 at 5:27 PM, Dmitry Vyukov [off-list ref] wrote:

On Tue, Jan 12, 2016 at 2:23 PM, Dmitry Vyukov [off-list ref] wrote:

quoted

On Tue, Jan 12, 2016 at 2:16 PM, Herbert Xu [off-list ref] wrote:

quoted

On Tue, Jan 12, 2016 at 10:27:44AM +0100, Dmitry Vyukov wrote:

quoted

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.