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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Sergei Trofimovich <slyich@gmail.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] objtool: check: give big enough buffer for pv_ops
Date: Thu, 20 Jan 2022 15:09:32 -0800	[thread overview]
Message-ID: <20220120230932.vgd3sj4yuk7mhmno@treble> (raw)
In-Reply-To: <20220120225810.zqpbug6oj52c34cg@treble>

On Thu, Jan 20, 2022 at 02:58:13PM -0800, Josh Poimboeuf wrote:
> On Fri, Jan 14, 2022 at 09:53:07AM +0100, Peter Zijlstra wrote:
> > On Fri, Jan 14, 2022 at 07:57:56AM +0000, Sergei Trofimovich wrote:
> > > On gcc-12 build fails flagging possible buffer overflow:
> > > 
> > >     check.c: In function 'validate_call':
> > >     check.c:2865:58: error: '%d' directive output may be truncated writing between 1 and 10 bytes into a region of size 9 [-Werror=format-truncation=]
> > >      2865 |                 snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
> > >           |                                                          ^~
> > > 
> > > I think it's a valid warning:
> > > 
> > >     static char pvname[16];
> > >     int idx;
> > >     ...
> > >     idx = (rel->addend / sizeof(void *));
> > >     snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
> > > 
> > > we have only 7 chars for %d while it could take up to 9.
> > 
> > Right, very unlikely to have that many pv_ops, but it doesn't hurt to
> > fix this.
> > 
> > Thanks!
> 
> Alternatively, 'idx' could just be unsigned char, since pv_ops only has
> about ~80 entries max, but either way works for me.  I'll queue it up.

Sergei, can you send a v2 with a valid Signed-off-by tag?

-- 
Josh


  reply	other threads:[~2022-01-20 23:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-14  7:57 [PATCH] objtool: check: give big enough buffer for pv_ops Sergei Trofimovich
2022-01-14  8:53 ` Peter Zijlstra
2022-01-20 22:58   ` Josh Poimboeuf
2022-01-20 23:09     ` Josh Poimboeuf [this message]
2022-01-20 23:37       ` [PATCH v2] " Sergei Trofimovich
2022-01-31 12:04         ` [tip: objtool/urgent] objtool: Fix truncated string warning tip-bot2 for Sergei Trofimovich

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