From: Alexey Dobriyan <adobriyan@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2] ELF: add and use SUPPRESS_WARN_UNUSED_RESULT
Date: Sat, 26 Jun 2021 09:40:59 +0300 [thread overview]
Message-ID: <YNbL+2dIVeZlNo6V@localhost.localdomain> (raw)
In-Reply-To: <20210625163040.a15af04872959da9af161fca@linux-foundation.org>
On Fri, Jun 25, 2021 at 04:30:40PM -0700, Andrew Morton wrote:
> On Sat, 26 Jun 2021 00:13:12 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote:
>
> > Last write to the "error" variable in load_elf_binary() is dead write.
> >
> > Add and use SUPPRESS_WARN_UNUSED_RESULT macro to express intent better.
> >
> > Credit goes to Ed Catmur:
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34
> >
> > Macro doesn't work for WUR functions returning structures and unions,
> > but it will work when gcc copies clang.
> >
> > ...
> >
> > #define __must_check __attribute__((__warn_unused_result__))
> > +/*
> > + * "(void)" is enough for clang but not for gcc.
> > + */
> > +#define SUPPRESS_WARN_UNUSED_RESULT (void)!
>
> That macro is rather ugly. Hopefully we won't really need it - how
> many such sites are there in a full kernel build anyway?
I don't know really. And they're hard to find because "(void)" doesn't
work and not everything is marked as WUR.
copy_from_user/copy_to_user are WUR but get_user/put_user aren't.
Logically they should bed. And if put_user() is WUR then I know another
place inside fork:
if (clone_flags & CLONE_PARENT_SETTID)
put_user(nr, args->parent_tid);
prev parent reply other threads:[~2021-06-26 6:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 19:52 [PATCH] ELF: add and use SUPRESS_WARN_UNUSED_RESULT Alexey Dobriyan
2021-06-25 20:34 ` Miguel Ojeda
2021-06-25 21:10 ` Alexey Dobriyan
2021-06-25 21:11 ` Randy Dunlap
2021-06-25 21:57 ` Miguel Ojeda
2021-06-26 6:44 ` [PATCH] ELF: add and use SUPRESS_WARN_UNUSED_RESULT\ Alexey Dobriyan
2021-06-26 14:29 ` Miguel Ojeda
2021-06-25 21:13 ` [PATCH v2] ELF: add and use SUPPRESS_WARN_UNUSED_RESULT Alexey Dobriyan
2021-06-25 23:30 ` Andrew Morton
2021-06-26 2:05 ` Linus Torvalds
2021-06-26 2:37 ` Al Viro
2021-06-26 3:13 ` Linus Torvalds
2021-06-26 6:40 ` Alexey Dobriyan [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YNbL+2dIVeZlNo6V@localhost.localdomain \
--to=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ojeda@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).