Re: [patch] perf: Fix build failure on OpenSuse userspace

[Arnaud Lacombe]

Hi,

On Fri, May 4, 2012 at 3:09 AM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
>> On Thu, May 03, 2012 at 11:01:54PM -0400, Arnaud Lacombe wrote:
>> > Hi,
>> >
>> > On Thu, May 3, 2012 at 10:47 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>> > > On Thu, May 03, 2012 at 10:35:02PM -0400, Arnaud Lacombe wrote:
>> > >> Hi,
>> > >>
>> > >> On Thu, May 3, 2012 at 10:29 PM, Arnaud Lacombe <lacombar@xxxxxxxxx> wrote:
>> > >> > [...]
>> > >> > [0]: http://pkgs.fedoraproject.org/gitweb/?p=flex.git;a=blob;f=flex-2.5.35-hardening.patch;h=7d608ea2371fa3295bdb8eb97c15eeb03029c02b;hb=HEAD
>> > >> >
>> > >> as a side note, this patch sounds more being about "silencing" than
>> > >> "hardening"...
>> > >
>> > > That's nice, but I can build the perf version in 3.3 just fine, so
>> > > something broke here (hint, build regression.)  Do I have to bisect it
>> > > down to find the problem?
>> > >
>> > there is most likely nothing to bisect, `perf' seems to have never
>> > required any parser before 3.4. The way the rest of the tools
>> > (especially `kconfig', `genksyms' and `dtc') manage parsers is via
>> > pre-generated .[ch]_shipped version of the lexer/tokenizer. It's been
>> > working well for a long time as such. `perf' will certainly have to
>> > follow the same path.
>>
>> Well, it can allow bison to run, but just don't break the build if the
>> generated code it creates happens to contain warnings.
>>
>> I'm using bison 2.5 and flex 2.5.35, and my phone number is...
>>
>> Like this really matters?  This needs to work for everyone, if not, you
>> better put the specific version numbers you need to require in the
>> Documentation/Changes file.
>>
>> So, how do I fix this?
>
> Does the (untested) patch below help?
>
> If not then please paste me the build failure output (it will
> most likely change due to the patch), and until we fix this
> build regression on OpenSuse userspace you can work it around
> via:
>
>  make WERROR=0
>
> Thanks,
>
>        Ingo
>
> diff --git a/tools/perf/Makefile b/tools/perf/Makefile
> index 7055a00..3174e9b 100644
> --- a/tools/perf/Makefile
> +++ b/tools/perf/Makefile
> @@ -729,10 +729,10 @@ $(OUTPUT)perf.o perf.spec \
>  # over the general rule for .o
>
>  $(OUTPUT)util/%-flex.o: $(OUTPUT)util/%-flex.c $(OUTPUT)PERF-CFLAGS
> -       $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) -Iutil/ -Wno-redundant-decls -Wno-switch-default -Wno-unused-function $<
> +       $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) -Iutil/ -Wno-redundant-decls -Wno-switch-default -Wno-unused-function -Wno-unused-parameter $<
>
>  $(OUTPUT)util/%-bison.o: $(OUTPUT)util/%-bison.c $(OUTPUT)PERF-CFLAGS
> -       $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) -DYYENABLE_NLS=0 -DYYLTYPE_IS_TRIVIAL=0 -Iutil/ -Wno-redundant-decls -Wno-switch-default -Wno-unused-function $<
> +       $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) -DYYENABLE_NLS=0 -DYYLTYPE_IS_TRIVIAL=0 -Iutil/ -Wno-redundant-decls -Wno-switch-default -Wno-unused-function -Wno-unused-parameter $<
>
>  $(OUTPUT)%.o: %.c $(OUTPUT)PERF-CFLAGS
>        $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
>
You can find the build failure log in
<20120503215748.GA18995@xxxxxxxxx>, pasted here for reference:

    CC util/parse-events-flex.o
<stdout>: In function ‘yy_get_next_buffer’:
<stdout>:1510:3: error: comparison between signed and unsigned integer
expressions [-Werror=sign-compare]
util/parse-events.l: In function ‘parse_events_lex’:
util/parse-events.l:122:1: error: ignoring return value of
‘fwrite’, declared with attribute warn_unused_result
[-Werror=unused-result]
cc1: all warnings being treated as errors

So I doubt -Wno-unused-parameter will do any good here.

How about my solution, pre-generating the lexer/tokenizer ? It has
been used without trouble in other place of the tree for years. I
don't really see the point of micro-managing flex/bison issue here.

 - Arnaud
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/