Subject: Re: linux-next: build failure after merge of the final tree (tip tree related)

From: Ingo Molnar <[email-masked]>
Date: Thu, 14 Oct 2010 08:31:27 +0200

* Stephen Rothwell <[email-masked]> wrote:

> Hi all,
> 
> After merging the final tree, linux-next builds (arm corgi_defconfig,
> spitz_defconfig) fail like this:
> 
> arch/arm/kernel/perf_event.c: In function 'armpmu_event_init':
> arch/arm/kernel/perf_event.c:543: error: request for member 'num_events' in something
 not a structure or union
> 
> Caused by commit 15ac9a395a753cb28c674e7ea80386ffdff21785 ("perf: Remove
> the sysfs bits").

Thanks, fixed.

> This seems to have broken in next-20100913 and noone has noticed/bothered
> to fix it.

What appears to have happened is the following: the build bug depends on 
CONFIG_HW_PERF_EVENTS=y, which is off by default on ARM (which default 
to a v5 CPU type - while hw pmu support is for v6+ cpus).

So the regular ARM defconfig built fine both in -next and here in the 
latest perf/core tree:

  testing        arm:  -git:  pass (    0),  -tip:  pass (    4)

Some new change in linux-next appears to have turned on HW_PERF_EVENTS 
elsewhere which you thus tested for the first time - which triggered the 
build bug.

Thanks,

	Ingo