Re: linux-next failing build due to missing cubictcp_state symbol

From: Jiri Slaby <jslaby@suse.com>
To: "Michal Suchánek" <msuchanek@suse.de>, "Jiri Olsa" <jolsa@redhat.com>
Cc: Yonghong Song <yhs@fb.com>,
	linux-kernel@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	"David S. Miller" <davem@davemloft.net>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	David Ahern <dsahern@kernel.org>,
	Jakub Kicinski <kuba@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Song Liu <songliubraving@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	Jiri Olsa <jolsa@kernel.org>,
	Jesper Dangaard Brouer <brouer@redhat.com>
Subject: Re: linux-next failing build due to missing cubictcp_state symbol
Date: Sat, 1 May 2021 08:45:50 +0200	[thread overview]
Message-ID: <3d148516-0472-8f0a-085b-94d68c5cc0d5@suse.com> (raw)
In-Reply-To: <20210430174723.GP15381@kitsune.suse.cz>

On 30. 04. 21, 19:47, Michal Suchánek wrote:
> CC another Jiri
> 
> On Tue, Apr 27, 2021 at 02:12:37PM +0200, Michal Suchánek wrote:
>> On Mon, Apr 26, 2021 at 09:16:36PM +0200, Jiri Olsa wrote:
>>> On Mon, Apr 26, 2021 at 06:03:19PM +0200, Jiri Olsa wrote:
>>>> On Mon, Apr 26, 2021 at 08:41:49AM -0700, Yonghong Song wrote:
>>>>>
>>>>>
>>>>> On 4/26/21 5:14 AM, Michal Suchánek wrote:
>>>>>> On Mon, Apr 26, 2021 at 02:12:20PM +0200, Michal Suchánek wrote:
>>>>>>> On Mon, Apr 26, 2021 at 01:32:15PM +0200, Michal Suchánek wrote:
>>>>>>>> On Sun, Apr 25, 2021 at 01:15:45PM +0200, Michal Suchánek wrote:
>>>>>>>>> On Fri, Apr 23, 2021 at 07:55:28PM +0200, Michal Suchánek wrote:
>>>>>>>>>> On Fri, Apr 23, 2021 at 07:41:29AM -0700, Yonghong Song wrote:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 4/23/21 6:05 AM, Michal Suchánek wrote:
>>>>>>>>>>>> Hello,
>>>>>>>>>>>>
>>>>>>>>>>>> I see this build error in linux-next (config attached).
>>>>>>>>>>>>
>>>>>>>>>>>> [ 4939s]   LD      vmlinux
>>>>>>>>>>>> [ 4959s]   BTFIDS  vmlinux
>>>>>>>>>>>> [ 4959s] FAILED unresolved symbol cubictcp_state
>>>>>>>>>>>> [ 4960s] make[1]: ***
>>>>>>>>>>>> [/home/abuild/rpmbuild/BUILD/kernel-vanilla-5.12~rc8.next.20210422/linux-5.12-rc8-next-20210422/Makefile:1277:
>>>>>>>>>>>> vmlinux] Error 255
>>>>>>>>>>>> [ 4960s] make: *** [../Makefile:222: __sub-make] Error 2
>>>>
>>>> this one was reported by Jesper and was fixed by upgrading pahole
>>>> that contains the new function generation fixes (v1.19)
>>>>
>>>>>>>>>>>
>>>>>>>>>>> Looks like you have DYNAMIC_FTRACE config option enabled already.
>>>>>>>>>>> Could you try a later version of pahole?
>>>>>>>>>>
>>>>>>>>>> Is this requireent new?
>>>>>>>>>>
>>>>>>>>>> I have pahole 1.20, and master does build without problems.
>>>>>>>>>>
>>>>>>>>>> If newer version is needed can a check be added?
>>>>>>>>>
>>>>>>>>> With dwarves 1.21 some architectures are fixed and some report other
>>>>>>>>> missing symbol. Definitely an improvenent.
>>>>>>>>>
>>>>>>>>> I see some new type support was added so it makes sense if that type is
>>>>>>>>> used the new dwarves are needed.
>>>>>>>>
>>>>>>>> Ok, here is the current failure with dwarves 1.21 on 5.12:
>>>>>>>>
>>>>>>>> [ 2548s]   LD      vmlinux
>>>>>>>> [ 2557s]   BTFIDS  vmlinux
>>>>>>>> [ 2557s] FAILED unresolved symbol vfs_truncate
>>>>>>>> [ 2558s] make[1]: ***
>>>>>>>> [/home/abuild/rpmbuild/BUILD/kernel-kvmsmall-5.12.0/linux-5.12/Makefile:1213:
>>>>>>>> vmlinux] Error 255
>>>>>
>>>>> This is PPC64, from attached config:
>>>>>    CONFIG_PPC64=y
>>>>> I don't have environment to cross-compile for PPC64.
>>>>> Jiri, could you take a look? Thanks!
>>>>
>>>> looks like vfs_truncate did not get into BTF data,
>>>> I'll try to reproduce

_None_ of the functions are generated by pahole -J from debuginfo on 
ppc64. debuginfo appears to be correct. Neither pahole -J fs/open.o 
works correctly. collect_functions in dwarves seems to be defunct on 
ppc64... "functions" array is bogus (so find_function -- the bsearch -- 
fails). I didn't have more time to continue debugging. This is where I 
stopped.

regards,
-- 
js
suse labs