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Date:   Tue, 22 Mar 2022 08:37:07 -0700
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Subject: Re: [TREE] "Fast Kernel Headers" Tree -v3
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To:     Kari Argillander <kari.argillander@stargateuniverse.net>,
        Ingo Molnar <mingo@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>, kari.argillander@gmail.com
References: <Ydm7ReZWQPrbIugn@gmail.com> <YjBr10JXLGHfEFfi@gmail.com>
 <CAKBF=pvWzuPx0JB3XZ-v+i7KGbhMQTgH6xtii_Bed+qKRFx+ww@mail.gmail.com>
From:   Randy Dunlap <rdunlap@infradead.org>
In-Reply-To: <CAKBF=pvWzuPx0JB3XZ-v+i7KGbhMQTgH6xtii_Bed+qKRFx+ww@mail.gmail.com>
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Hi Kari,

On 3/22/22 00:59, Kari Argillander wrote:
> 15.3.2022 12.35 Ingo Molnar (mingo@kernel.org) wrote:
>>
>> This is -v3 of the "Fast Kernel Headers" tree, which is an ongoing rework
>> of the Linux kernel's header hierarchy & header dependencies, with the dual
>> goals of:
>>
>>  - speeding up the kernel build (both absolute and incremental build times)
>>
>>  - decoupling subsystem type & API definitions from each other
>>
>> The fast-headers tree consists of over 25 sub-trees internally, spanning
>> over 2,300 commits, which can be found at:
>>
>>     git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git master
> 
> I have had problems to build master branch (defconfig) with gcc9
>     gcc (Ubuntu 9.4.0-1ubuntu1~20.04) 9.4.0
> 
> I did also test v2 and problems where there too. I have no problem with gcc10 or
> Clang11. Error I get is:
> 
> In file included from ./include/linux/rcuwait_api.h:7,
>                  from ./include/linux/rcuwait.h:6,
>                  from ./include/linux/irq_work.h:7,
>                  from ./include/linux/perf_event_types.h:44,
>                  from ./include/linux/perf_event_api.h:17,
>                  from arch/x86/kernel/kprobes/opt.c:8:
> ./include/linux/rcuwait_api.h: In function ‘rcuwait_active’:
> ./include/linux/rcupdate.h:328:9: error: dereferencing pointer to
> incomplete type ‘struct task_struct’
>   328 |  typeof(*p) *local = (typeof(*p) *__force)READ_ONCE(p); \
>       |         ^
> ./include/linux/rcupdate.h:439:31: note: in expansion of macro
> ‘__rcu_access_pointer’
>   439 | #define rcu_access_pointer(p) __rcu_access_pointer((p),
> __UNIQUE_ID(rcu), __rcu)
>       |                               ^~~~~~~~~~~~~~~~~~~~
> ./include/linux/rcuwait_api.h:15:11: note: in expansion of macro
> ‘rcu_access_pointer’
>    15 |  return !!rcu_access_pointer(w->task);
> 
>     Argillander

You could try the patch here:
https://lore.kernel.org/all/917e9ce0-c8cf-61b2-d1ba-ebf25bbd979d@infradead.org/

although the build error that it fixes doesn't look exactly the same
as yours.

>> There's various changes in -v3, and it's now ported to the latest kernel
>> (v5.17-rc8).
>>
>> Diffstat difference:
>>
>>  -v2: 25332 files changed, 178498 insertions(+), 74790 deletions(-)
>>  -v3: 25513 files changed, 180947 insertions(+), 74572 deletions(-)


-- 
~Randy