From: Kees Cook <keescook@chromium.org>
To: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Patrick McLean <chutzpah@gentoo.org>,
"Maciej S. Szmigiero" <mail@maciej.szmigiero.name>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] kconfig.h: Include compiler types to avoid missed struct attributes
Date: Thu, 22 Feb 2018 13:22:37 -0800 [thread overview]
Message-ID: <CAGXu5jK2BA03xi6UCM66buAXemc1SdOmtGsxOSUdGNidxb4Hsw@mail.gmail.com> (raw)
In-Reply-To: <66556bf7-3e67-5793-081e-76a01f598374@prevas.dk>
On Thu, Feb 22, 2018 at 1:07 PM, Rasmus Villemoes
<rasmus.villemoes@prevas.dk> wrote:
> On 2018-02-22 19:04, Linus Torvalds wrote:
>>
>> Lookie here (in a fully built tree):
>>
>> find . -name '*.o.cmd' |
>> xargs grep -L linux/compiler_types.h |
>> xargs grep -l linux/kconfig.h |
>> while read i; do
>> j=$(echo $i | sed 's/\.o.cmd$/\.c/' | sed 's:/\.:/:');
>> test -f $j && echo $j;
>> done
>>
>> shows that a number of files don't end up depending on that header
>> file, even though it's included (that "grep -l linux/kconfig,h"
>> triggers on the command itself having that "-include linux/kconfig.h"
>> line).
>>
>> It looks like "gcc -M" just doesn't list any files that get included
>> on the command line with "-include".
>
> It does, both per the documentation and testing it. But fixdep
> explicitly removes include/linux/kconfig.h along with
> include/generated/autoconf.h and a few others. So when you rebuilt after
> adding the #include to kconfig.h, I think nothing actually got built,
> and no new .o.cmd files got generated.
>
> Doing a clean build does make include/linux/compiler_{types,gcc}.h and
> the various fake include/config/.... they "depend" on appear in e.g.
> lib/.clz_tab.o.cmd.
I'm seeing the same. If I do:
$ find . -name '*.o.cmd' | xargs rm
$ make allmodconfig
$ make -j...
...
$ find-command-above...
I get no hits. And doing spot-testing shows dep changes are detected:
$ ls -l fs/nfsd/nfs4xdr.o
-rw-rw-r-- 1 kees kees 276088 Feb 22 13:15 fs/nfsd/nfs4xdr.o
$ make fs/nfsd/nfs4xdr.o
...generated-files-only...
$ ls -l fs/nfsd/nfs4xdr.o
-rw-rw-r-- 1 kees kees 276088 Feb 22 13:15 fs/nfsd/nfs4xdr.o
$ touch include/linux/compiler_types.h
$ make fs/nfsd/nfs4xdr.o
...various...
CC [M] fs/nfsd/nfs4xdr.o
$ ls -l fs/nfsd/nfs4xdr.o
-rw-rw-r-- 1 kees kees 276088 Feb 22 13:21 fs/nfsd/nfs4xdr.o
Am I missing something?
> The whole point of fixdep and the include/config hierarchy is to be able
> to remove the dependency on autoconf.h, but I'm not sure I understand
> why kconfig.h itself is also forcibly removed.
Is there a mode where we're now rebuilding too much?
-Kees
--
Kees Cook
Pixel Security
next prev parent reply other threads:[~2018-02-22 21:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 17:41 [PATCH v3] kconfig.h: Include compiler types to avoid missed struct attributes Kees Cook
2018-02-22 18:04 ` Linus Torvalds
2018-02-22 19:57 ` Kees Cook
2018-02-22 20:17 ` Linus Torvalds
2018-02-22 21:07 ` Rasmus Villemoes
2018-02-22 21:22 ` Kees Cook [this message]
2018-02-22 21:23 ` Linus Torvalds
2018-02-22 21:54 ` Linus Torvalds
2018-02-22 21:34 ` Rasmus Villemoes
2018-02-22 21:56 ` Linus Torvalds
2018-02-28 19:17 ` [PATCH 1/3] fixdep: remove stale references to uml-config.h Rasmus Villemoes
2018-02-28 19:17 ` [PATCH 2/3] fixdep: remove some false CONFIG_ matches Rasmus Villemoes
2018-02-28 19:17 ` [PATCH 3/3] fixdep: do not ignore kconfig.h Rasmus Villemoes
2018-03-05 4:52 ` Masahiro Yamada
2018-03-05 8:15 ` Rasmus Villemoes
2018-03-05 9:38 ` Masahiro Yamada
2018-03-05 14:49 ` Masahiro Yamada
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