Re: [GIT PULL] kbuild updates for v4.7-rc1

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [GIT PULL] kbuild updates for v4.7-rc1
Date	2016-05-27 07:30 +0200
Message-ID	<rDivn-7KL-1@gated-at.bofh.it> (permalink)
References	<rDaet-2yj-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, May 26, 2016 at 1:33 PM, Michal Marek <mmarek@suse.com> wrote:
>
>   git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild.git kbuild

This pull results in new warnings.

I get new "may be uninitialized" warnings now for me allmodconfig
build, and while I didn't look at them all, the one I looked at was
just entirely crap:

   fs/gfs2/dir.c: In function ‘dir_split_leaf.isra.16’:
   fs/gfs2/dir.c:1021:8: warning: ‘leaf_no’ may be used uninitialized
in this function [-Wmaybe-uninitialized]
     error = get_leaf(dip, leaf_no, &obh);
           ^

yeah no, leaf_no is initialized a few lines up by

        error = get_leaf_nr(dip, index, &leaf_no);

and the fact that gcc can't follow the trivial  error handling is not
our fault. It looks *so* trivial that I wonder why.

That said, I don't see exactly what in the pull request causes this.

My reading of the diff seems to say that you are actually adding
*more* cases of -Wno-maybe-uninitialized, not less.

So I suspect it's almost accidental in just how the Kconfig option
CC_OPTIMIZE_FOR_PERFORMANCE happened, which in turn probably just
changes the options for "make allmiodconfig", and it now picks a
non-size-optimized build that always showed those warnings and I just
didn't see them.

Annoying. I've pulled it, but I wish you would look at this.

              Linus

Thread

[GIT PULL] kbuild updates for v4.7-rc1 Michal Marek <mmarek@suse.com> - 2016-05-26 22:40 +0200
  Re: [GIT PULL] kbuild updates for v4.7-rc1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-05-27 07:30 +0200
    Re: [GIT PULL] kbuild updates for v4.7-rc1 Arnd Bergmann <arnd@arndb.de> - 2016-05-27 14:40 +0200
      Re: [GIT PULL] kbuild updates for v4.7-rc1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-05-27 19:30 +0200
        Re: [GIT PULL] kbuild updates for v4.7-rc1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-05-27 20:30 +0200
        Re: [GIT PULL] kbuild updates for v4.7-rc1 Arnd Bergmann <arnd@arndb.de> - 2016-05-27 22:10 +0200
          Re: [GIT PULL] kbuild updates for v4.7-rc1 Linus Torvalds <torvalds@linux-foundation.org> - 2016-05-27 22:30 +0200
            Re: [GIT PULL] kbuild updates for v4.7-rc1 Arnd Bergmann <arnd@arndb.de> - 2016-05-27 23:40 +0200
            Re: [GIT PULL] kbuild updates for v4.7-rc1 Al Viro <viro@ZenIV.linux.org.uk> - 2016-05-28 00:00 +0200

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