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From: Gustavo Luiz Duarte <gustavold@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
	Gustavo Luiz Duarte <gustavold@linux.ibm.com>,
	linuxppc-dev@lists.ozlabs.org
Cc: mikey@neuling.org, gromero@linux.ibm.com
Subject: Re: [PATCH v2 2/3] selftests/powerpc: Add tm-signal-pagefault test
Date: Thu, 6 Feb 2020 19:16:05 -0300	[thread overview]
Message-ID: <4c4295c6-c2d3-0e83-68aa-dc8770c80381@linux.vnet.ibm.com> (raw)
In-Reply-To: <8736bp38o7.fsf@mpe.ellerman.id.au>



On 2/5/20 2:27 AM, Michael Ellerman wrote:
> Gustavo Luiz Duarte <gustavold@linux.ibm.com> writes:
>> This test triggers a TM Bad Thing by raising a signal in transactional state
>> and forcing a pagefault to happen in kernelspace when the kernel signal
>> handling code first touches the user signal stack.
>>
>> This is inspired by the test tm-signal-context-force-tm but uses userfaultfd to
>> make the test deterministic. While this test always triggers the bug in one
>> run, I had to execute tm-signal-context-force-tm several times (the test runs
>> 5000 times each execution) to trigger the same bug.
> 
> Using userfaultfd is a very nice touch. But it's not always enabled,
> which leads to eg:
> 
>    root@mpe-ubuntu-le:~# /home/michael/tm-signal-pagefault
>    test: tm_signal_pagefault
>    tags: git_version:v5.5-9354-gc1e346e7fc44
>    userfaultfd() failed: Function not implemented
>    failure: tm_signal_pagefault
> 
> It would be nice if that resulted in a skip, not a failure.
> 
> It looks like it shouldn't be too hard to skip if the userfaultfd call
> returns ENOSYS.

Good point. I will fix that on v3.

> 
> cheers
> 

  reply	other threads:[~2020-02-06 22:18 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-03 16:09 [PATCH v2 1/3] powerpc/tm: Clear the current thread's MSR[TS] after treclaim Gustavo Luiz Duarte
2020-02-03 16:09 ` [PATCH v2 2/3] selftests/powerpc: Add tm-signal-pagefault test Gustavo Luiz Duarte
2020-02-05  5:27   ` Michael Ellerman
2020-02-06 22:16     ` Gustavo Luiz Duarte [this message]
2020-02-03 16:09 ` [PATCH v2 3/3] selftests/powerpc: Don't rely on segfault to rerun the test Gustavo Luiz Duarte
2020-02-05  4:58 ` [PATCH v2 1/3] powerpc/tm: Clear the current thread's MSR[TS] after treclaim Michael Neuling
2020-02-06 22:13   ` Gustavo Luiz Duarte
2020-02-07  0:41     ` Michael Neuling
2020-02-05 14:45 ` Sasha Levin

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