From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julia Lawall Date: Wed, 05 Dec 2018 08:11:56 +0000 Subject: Re: [PATCH] powerpc/ipic: Fix a bounds check in ipic_set_priority() Message-Id: List-Id: References: <20181203144834.ocxntjflfz2idxrb@kili.mountain> <87sgzchcw8.fsf@concordia.ellerman.id.au> In-Reply-To: <87sgzchcw8.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Michael Ellerman Cc: Kim Phillips , kernel-janitors@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org, Dan Carpenter On Wed, 5 Dec 2018, Michael Ellerman wrote: > Hi Dan, > > Thanks for the patch. > > Dan Carpenter writes: > > The ipic_info[] array only has 95 elements so I have made the bounds > > check smaller to prevent a read overflow. It was Smatch that found > > this issue: > > > > arch/powerpc/sysdev/ipic.c:784 ipic_set_priority() > > error: buffer overflow 'ipic_info' 95 <= 127 > > > > Signed-off-by: Dan Carpenter > > --- > > I wasn't able to find any callers of this code. Maybe we removed the > > last one in commit b9f0f1bb2bca ("[POWERPC] Adapt ipic driver to new > > host_ops interface, add set_irq_type to set IRQ sense"). So perhaps we > > should just remove it. I'm not really comfortable doing that myself, > > because I don't know the code well enough and can't build test > > it properly. > > Hah wow, last usage removed in 2006! > > I don't see any mention of it since then, so I'll remove it. If it > breaks something we can put it back. > > Can smatch help us find things like this that are defined non-static but > never used? I wrote a Coccinelle script for this, that just uses grep. Of course the results need checking because uses can be constructed within macros using #. Are things that are defined static but are never used useful to keep around? julia