Re: mmotm 2019-12-10-19-14 uploaded (objtool: func() falls through)

From: Randy Dunlap <rdunlap@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	broonie@kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-next@vger.kernel.org, mhocko@suse.cz,
	mm-commits@vger.kernel.org, sfr@canb.auug.org.au,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: mmotm 2019-12-10-19-14 uploaded (objtool: func() falls through)
Date: Fri, 17 Jan 2020 14:15:54 -0800	[thread overview]
Message-ID: <d1dc6614-9089-62a8-e303-84b9d57297a3@infradead.org> (raw)
In-Reply-To: <20200117181121.3h72dajey7oticbf@treble>

On 1/17/20 10:11 AM, Josh Poimboeuf wrote:
> On Thu, Dec 12, 2019 at 02:58:11PM -0600, Josh Poimboeuf wrote:
>> On Thu, Dec 12, 2019 at 12:21:17PM -0800, Randy Dunlap wrote:
>>> On 12/12/19 10:48 AM, Josh Poimboeuf wrote:
>>>> On Wed, Dec 11, 2019 at 08:31:08AM -0800, Randy Dunlap wrote:
>>>>> On 12/10/19 7:14 PM, Andrew Morton wrote:
>>>>>> The mm-of-the-moment snapshot 2019-12-10-19-14 has been uploaded to
>>>>>>
>>>>>>    http://www.ozlabs.org/~akpm/mmotm/
>>>>>>
>>>>>> mmotm-readme.txt says
>>>>>>
>>>>>> README for mm-of-the-moment:
>>>>>>
>>>>>> http://www.ozlabs.org/~akpm/mmotm/
>>>>>>
>>>>>> This is a snapshot of my -mm patch queue.  Uploaded at random hopefully
>>>>>> more than once a week.
>>>>>>
>>>>>> You will need quilt to apply these patches to the latest Linus release (5.x
>>>>>> or 5.x-rcY).  The series file is in broken-out.tar.gz and is duplicated in
>>>>>> http://ozlabs.org/~akpm/mmotm/series
>>>>>>
>>>>>> The file broken-out.tar.gz contains two datestamp files: .DATE and
>>>>>> .DATE-yyyy-mm-dd-hh-mm-ss.  Both contain the string yyyy-mm-dd-hh-mm-ss,
>>>>>> followed by the base kernel version against which this patch series is to
>>>>>> be applied.
>>>>>
>>>>> on x86_64:
>>>>>
>>>>> drivers/hwmon/f71882fg.o: warning: objtool: f71882fg_update_device() falls through to next function show_pwm_auto_point_temp_hyst()
>>>>> drivers/ide/ide-probe.o: warning: objtool: hwif_register_devices() falls through to next function hwif_release_dev()
>>>>> drivers/ide/ide-probe.o: warning: objtool: ide_host_remove() falls through to next function ide_disable_port()
>>>>
>>>> Randy, can you share the .o files?
>>>
>>> Sure. They are attached.
>>
>> These look like compiler bugs to me... execution is falling off the edge
>> of the functions for no apparent reason.  Could potentially be triggered
>> by the '#define if' trace code.
> 
> Randy, do you happen to have a config which triggers the above bugs?  I
> can reduce the test cases and open a GCC bug.
> 

No, but I'll try to recreate the issue and get back to you.

-- 
~Randy