linux-kernel - Re: [PATCH v2 1/2] jump_label: Explicitly disable jump labels in _

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20180218131538.5nmfce2aepcg2bpr@gmail.com>
Date:   Sun, 18 Feb 2018 14:15:38 +0100
From:   Ingo Molnar <mingo@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     Josh Poimboeuf <jpoimboe@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Jason Baron <jbaron@...mai.com>, Borislav Petkov <bp@...e.de>
Subject: Re: [PATCH v2 1/2] jump_label: Explicitly disable jump labels in
 __init code


* Ingo Molnar <mingo@...nel.org> wrote:

> 2) code robustness 
> 
> For example:
> 
>         for (i = 0; i < 10; i++)
>                 if (foo)
>                         bar(i);
>                 baz(i);
> 
> Is probably buggy code, although technically it's valid syntax and will compile 
> just fine.
> 
> If all multi-line statements have curly braces then this type of bug cannot occur:
> 
>         for (i = 0; i < 10; i++) {
>                 if (foo)
>                         bar(i);
>                 baz(i);
> 	}

Note that newer versions of GCC will warn about this pattern:

     warning: this ‘for’ clause does not guard
              this statement, but the latter is misleadingly indented as if it were guarded by the ‘for’

But the warning is pretty restrictive and GCC won't warn about slightly more 
complex patterns like:

          for (i = 0; i < 10; i++)
                  if (foo)
                          bar(i);
//                debug_fn();
                  baz(i);

Thanks,

	Ingo