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From: Michael Ellerman <mpe@ellerman.id.au>
To: Gustavo Luiz Duarte <gustavold@linux.ibm.com>,
	linuxppc-dev@lists.ozlabs.org
Cc: mikey@neuling.org, gromero@linux.ibm.com,
	Gustavo Luiz Duarte <gustavold@linux.ibm.com>
Subject: Re: [PATCH v2 2/3] selftests/powerpc: Add tm-signal-pagefault test
Date: Wed, 05 Feb 2020 16:27:52 +1100	[thread overview]
Message-ID: <8736bp38o7.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200203160906.24482-2-gustavold@linux.ibm.com>

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.

cheers

  reply	other threads:[~2020-02-05  5:29 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 [this message]
2020-02-06 22:16     ` Gustavo Luiz Duarte
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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