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From: Dave Martin <Dave.Martin@arm.com>
To: Cristian Marussi <cristian.marussi@arm.com>
Cc: andreyknvl@google.com, shuah@kernel.org,
	linux-kselftest@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 06/11] kselftest: arm64: fake_sigreturn_bad_magic
Date: Wed, 4 Sep 2019 11:47:50 +0100
Message-ID: <20190904104750.GO27757@arm.com> (raw)
In-Reply-To: <1ae402d4-4fe0-9541-4e18-d432f88fc6bb@arm.com>

On Wed, Sep 04, 2019 at 11:37:36AM +0100, Cristian Marussi wrote:
> On 04/09/2019 11:05, Dave Martin wrote:
> > On Fri, Aug 30, 2019 at 03:29:29PM +0100, Cristian Marussi wrote:
> >> Hi
> >>
> >> On 13/08/2019 17:25, Dave Martin wrote:
> >>> On Fri, Aug 02, 2019 at 06:02:55PM +0100, Cristian Marussi wrote:
> > 
> > [...]
> > 
> >>>> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_bad_magic.c
> > 
> > [...]
> > 
> >>>> +static int fake_sigreturn_bad_magic_run(struct tdescr *td,
> >>>> +					siginfo_t *si, ucontext_t *uc)
> >>>> +{
> >>>> +	size_t resv_sz, offset;
> >>>> +	struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
> >>>> +
> >>>> +	/* just to fill the ucontext_t with something real */
> >>>> +	if (!get_current_context(td, &sf.uc))
> >>>> +		return 1;
> >>>> +
> >>>> +	resv_sz = GET_SF_RESV_SIZE(sf);
> >>>> +	/*
> >>>> +	 * find the terminator, preserving existing headers
> >>>> +	 * and verify amount of spare room in __reserved area.
> >>>> +	 */
> >>>> +	head = get_terminator(shead, resv_sz, &offset);
> >>>> +	/*
> >>>> +	 * try stripping extra_context header when low on space:
> >>>> +	 * we need at least 2*HDR_SZ space ... one for the KSFT_BAD_MAGIC
> >>>> +	 * and the other for the usual terminator.
> >>>> +	 */
> >>>> +	if (head && resv_sz - offset < HDR_SZ * 2) {
> >>>
> >>> Can we factor out this logic for finding space in the signal frame?
> >>>
> >>> We do pretty much the same thing in all the fake_sigreturn tests...
> >>
> >> Ok
> >>>
> >>>> +		fprintf(stderr, "Low on space:%zd. Discarding extra_context.\n",
> >>>> +			resv_sz - offset);
> >>>> +		head = get_header(shead, EXTRA_MAGIC, resv_sz, &offset);
> >>>> +	}
> >>>> +	/* just give up and timeout if still not enough space */
> >>>
> >>> Do we actually time out?  I don't see where we actually wait, so doesn't
> >>> test_run() just fail immediately?
> >>>
> >>> The same applies to all the other fake_sigreturn tests too.
> >>>
> >> Right. It is probably a leftover.
> >>
> >> SIGALRM is used as an extreme measure to kill tests gone bad, but this
> >> can happen only once the fake sigframe has been effectively placed on the stack
> >> and sigreturned.
> > 
> > OK, so this gets reported as a test failure because with no SIGSEGV,
> > nothing ever sets td->pass?
> 
> Yes exactly. End result is based on value on td->pass, in case of abrupt
> termination or timeout nobody sets td->pass ever.
> > 
> > This is probably OK for now, though I wonder whether this should be
> > reported as a skipped test instead.
> > 
> > In case of doubt, reporting a failure is preferable anyway, since that
> > will encourage people actually to investigate what went wrong.
> > 
> 
> As of now I never skip a test in fact...also tests for unsupported features
> are built and run expecting a SIGILL, and reported as PASS in that case.

OK, just wanted to check I'd understood correcly.

Cheers
---Dave

  reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 17:02 [PATCH v3 00/11] Add arm64/signal initial kselftest support Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 01/11] kselftest: arm64: introduce new boilerplate code Cristian Marussi
2019-08-13 16:23   ` Dave Martin
2019-08-27 12:14     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 02/11] kselftest: arm64: adds first test and common utils Cristian Marussi
2019-08-06 15:50   ` Cristian Marussi
2019-08-07 15:42   ` Cristian Marussi
2019-08-09 10:54   ` Cristian Marussi
2019-08-09 11:16     ` Dave Martin
2019-08-09 12:20       ` Cristian Marussi
2019-08-09 12:32         ` Dave Martin
2019-08-12 12:43   ` Amit Kachhap
2019-08-13 13:22     ` Cristian Marussi
2019-08-14 10:22       ` Amit Kachhap
2019-08-27 14:24         ` Cristian Marussi
2019-08-13 16:24   ` Dave Martin
2019-08-28 17:34     ` Cristian Marussi
2019-09-03 15:34       ` Dave Martin
2019-09-03 16:08         ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 03/11] kselftest: arm64: mangle_pstate_invalid_daif_bits Cristian Marussi
2019-08-13 16:24   ` Dave Martin
2019-08-29 10:19     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 04/11] kselftest: arm64: mangle_pstate_invalid_mode_el Cristian Marussi
2019-08-13 16:24   ` Dave Martin
2019-08-29 11:50     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 05/11] kselftest: arm64: mangle_pstate_ssbs_regs Cristian Marussi
2019-08-13 16:25   ` Dave Martin
2019-08-29 15:35     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 06/11] kselftest: arm64: fake_sigreturn_bad_magic Cristian Marussi
2019-08-13 16:25   ` Dave Martin
2019-08-30 14:29     ` Cristian Marussi
2019-09-04 10:05       ` Dave Martin
2019-09-04 10:37         ` Cristian Marussi
2019-09-04 10:47           ` Dave Martin [this message]
2019-08-02 17:02 ` [PATCH v3 07/11] kselftest: arm64: fake_sigreturn_bad_size_for_magic0 Cristian Marussi
2019-08-13 16:25   ` Dave Martin
2019-08-30 14:49     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 08/11] kselftest: arm64: fake_sigreturn_missing_fpsimd Cristian Marussi
2019-08-13 16:26   ` Dave Martin
2019-08-30 14:55     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 09/11] kselftest: arm64: fake_sigreturn_duplicated_fpsimd Cristian Marussi
2019-08-13 16:26   ` Dave Martin
2019-08-30 15:11     ` Cristian Marussi
2019-08-02 17:02 ` [PATCH v3 10/11] kselftest: arm64: fake_sigreturn_bad_size Cristian Marussi
2019-08-13 16:26   ` Dave Martin
2019-08-30 15:21     ` Cristian Marussi
2019-08-02 17:03 ` [PATCH v3 11/11] kselftest: arm64: fake_sigreturn_misaligned_sp Cristian Marussi
2019-08-07 16:04   ` Cristian Marussi
2019-08-13 16:28     ` Dave Martin
2019-08-30 15:22       ` Cristian Marussi
2019-08-13 16:27   ` Dave Martin
2019-08-30 16:33     ` Cristian Marussi
2019-08-13 16:22 ` [PATCH v3 00/11] Add arm64/signal initial kselftest support Dave Martin
2019-08-30 16:40   ` Cristian Marussi
2019-09-02 10:53     ` Dave Martin
2019-09-02 11:30       ` Cristian Marussi

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