linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Jérémy Lefaure" <jeremy.lefaure@lse.epita.fr>
Cc: David Howells <dhowells@redhat.com>,
	linux-cachefs@redhat.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] FS-Cache: print hexadecimal value for special cookies type
Date: Fri, 21 Apr 2017 22:41:54 +0300	[thread overview]
Message-ID: <CAHp75VcNtnx5upkNwDeu3MSbaCp8DQtRUkm_MDA1pt3aVLT4Dg@mail.gmail.com> (raw)
In-Reply-To: <20170419203819.21951-1-jeremy.lefaure@lse.epita.fr>

On Wed, Apr 19, 2017 at 11:38 PM, Jérémy Lefaure
<jeremy.lefaure@lse.epita.fr> wrote:
> When building object-list.o, gcc 6 raises a warning on the sprintf call
> in fscache_objlist_show:
>
>   CC      fs/fscache/object-list.o
> fs/fscache/object-list.c: In function ‘fscache_objlist_show’:
> fs/fscache/object-list.c:265:19: warning: ‘sprintf’ may write a
> terminating nul past the end of the destination [-Wformat-overflow=]
>     sprintf(_type, "%02u", cookie->def->type);
>                    ^~~~~~
> fs/fscache/object-list.c:265:4: note: ‘sprintf’ output between 3 and 4
> bytes into a destination of size 3
>     sprintf(_type, "%02u", cookie->def->type);
>     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Moreover, the documentation says that we should have an hex value for
> special cookies (see Documentation/filesystems/caching/fscache.txt).
>
> Printing hexadecimal value for special cookies fixes the overflow
> warning and complies with the documentation.

If this is used by some user space tool the safest fix is to print in
BCD and fix documentation.

> Signed-off-by: Jérémy Lefaure <jeremy.lefaure@lse.epita.fr>
> ---
>  fs/fscache/object-list.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
> index 67f940892ef8..d51303124889 100644
> --- a/fs/fscache/object-list.c
> +++ b/fs/fscache/object-list.c
> @@ -262,7 +262,7 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
>                         type = "DT";
>                         break;
>                 default:
> -                       sprintf(_type, "%02u", cookie->def->type);
> +                       sprintf(_type, "%02x", cookie->def->type);
>                         type = _type;
>                         break;
>                 }
> --
> 2.12.2
>



-- 
With Best Regards,
Andy Shevchenko

  reply	other threads:[~2017-04-21 19:42 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-19 20:38 Jérémy Lefaure
2017-04-21 19:41 ` Andy Shevchenko [this message]
2017-04-21 23:09   ` Jérémy Lefaure
2017-04-24 21:47     ` Andy Shevchenko
2017-04-25 21:37       ` Jérémy Lefaure
2017-04-25 22:04         ` Andy Shevchenko
2017-04-27  0:31 ` [PATCH v2] FS-Cache: fix buffer size for decimal value of special cookie type Jérémy Lefaure
2017-04-27 15:03 ` [PATCH] FS-Cache: print hexadecimal value for special cookies type David Howells
2017-04-27 15:11   ` Jérémy Lefaure
2017-04-27 15:41   ` David Howells
2017-05-28  0:31   ` Jérémy Lefaure

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=CAHp75VcNtnx5upkNwDeu3MSbaCp8DQtRUkm_MDA1pt3aVLT4Dg@mail.gmail.com \
    --to=andy.shevchenko@gmail.com \
    --cc=dhowells@redhat.com \
    --cc=jeremy.lefaure@lse.epita.fr \
    --cc=linux-cachefs@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --subject='Re: [PATCH] FS-Cache: print hexadecimal value for special cookies type' \
    /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

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).