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Re: [PATCH v2] perf: xgene: Remove bogus IS_ERR() check

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On Thu, Oct 13, 2016 at 07:18:37PM +0100, Al Viro wrote:
> On Thu, Oct 13, 2016 at 11:09:16AM -0700, Tai Nguyen wrote:
> > In acpi_get_pmu_hw_inf we pass the address of a local variable to IS_ERR(),
> > which doesn't make sense, as the pointer must be a real, valid pointer.
> > This doesn't cause a functional problem, as IS_ERR() will evaluate as
> > false, but the check is bogus and causes static checkers to complain.
> 
> ... unless the test is actually a misspelled IS_ERR(res) and the current
> code is broken by effectively skipping it.

Sure.

In this case, res is a struct resource, so IS_ERR(res) is also bogus.

None of the pointer fields in struct resource are ever set to an ERR_PTR value,
so nothing in res is worth checking. Nothing else in the function prior to this
would be an ERR_PTR value either.

I believe this case was copy-paste and a thinko. There's some other error
handling in the file that does validly have to handle an ERR_PTR value.

Thanks,
Mark.

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[PATCH v2] perf: xgene: Remove bogus IS_ERR() check Tai Nguyen <ttnguyen@apm.com> - 2016-10-13 20:20 +0200
  Re: [PATCH v2] perf: xgene: Remove bogus IS_ERR() check Al Viro <viro@ZenIV.linux.org.uk> - 2016-10-13 20:20 +0200
    Re: [PATCH v2] perf: xgene: Remove bogus IS_ERR() check Mark Rutland <mark.rutland@arm.com> - 2016-10-14 02:50 +0200

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