linux-kernel - Re: [PATCH] seq_buf: avoid type mismatch for seq_buf

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: <CAK8P3a1ASxy3w62A16Ne9AkM2kfF5ZokYOfos53FSTQdkXha4Q@mail.gmail.com>
Date:   Mon, 26 Oct 2020 20:07:39 +0100
From:   Arnd Bergmann <arnd@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Ingo Molnar <mingo@...hat.com>, Jiri Kosina <jkosina@...e.cz>,
        Petr Mladek <pmladek@...e.cz>,
        Piotr Maziarz <piotrx.maziarz@...ux.intel.com>,
        Cezary Rojewski <cezary.rojewski@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] seq_buf: avoid type mismatch for seq_buf_init

On Mon, Oct 26, 2020 at 6:23 PM Steven Rostedt <rostedt@...dmis.org> wrote:
>
> On Mon, 26 Oct 2020 17:10:58 +0100
> Arnd Bergmann <arnd@...nel.org> wrote:
>
> > From: Arnd Bergmann <arnd@...db.de>
> >
> > Building with W=2 prints a number of warnings for one function that
> > has a pointer type mismatch:
> >
> > linux/seq_buf.h: In function 'seq_buf_init':
> > linux/seq_buf.h:35:12: warning: pointer targets in assignment from 'unsigned char *' to 'char *' differ in signedness [-Wpointer-sign]
>
> I've always hated the warning about char * and unsigned char *, as they are
> mostly meaningless. Yes, bugs happen with int to unsigned int conversions,
> but this is dealing with strings, where unsigned char * and char * are
> basically equivalent, except when it comes to one thing, which is why I
> prefer unsigned char * over char *, and that is printing out the numerical
> values of a buffer, if they go above 177, the char * prints the negative
> value, but unsigned char * keeps printing what you would expect.

I agree it's a super annoying warning, which is exactly why I sent the
fixes to shut it up in common headers. At least that way, building a specific
driver with W=2 will only show the warnings in that driver, rather than
those in header files as well.

> As this is just an annoyance (extra warnings), and not really a "fix", I'll
> queue it up for the next merge window.

Yes, that was the idea, thanks!

        Arnd