Re: [PATCH] perf tests: Fix false TEST_OK result for 'perf test hist'

[Jiri Olsa <jolsa@redhat.com>]

On Tue, Dec 15, 2015 at 04:18:44AM +0000, Wang Nan wrote:
> Commit 71d6de64feddd4b455555326fba2111b3006d9e0 ('perf test: Fix hist
> testcases when kptr_restrict is on') solves a double free problem when
> 'perf test hist' calling setup_fake_machine(). However, the result is
> still incorrect. For example:
> 
>  $ ./perf test -v 'filtering hist entries'
>  25: Test filtering hist entries                              :
>  --- start ---
>  test child forked, pid 4186
>  Cannot create kernel maps
>  test child finished with 0
>  ---- end ----
>  Test filtering hist entries: Ok
> 
> In this case the body of this test is not get executed at all, but the
> result is 'Ok'. I think 'Skip' should be better.
> 
> The reason is that *ALL* hists test cases forget to reset err after
> using it to hold an error code.
> 
> This patch ensure err is reset.
> 
> In case when kptr_restrict prevent normal user get kernel address, this
> test should be skipped, not fail. This patch uses linux/err.h to store
> error code in return value of setup_fake_machine(), and let 'EACCES' to
> indicate this problem.
> 
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka