From: Matthew Wilcox <willy@infradead.org>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-fsdevel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] xarray: unlock on error in xa_alloc()
Date: Fri, 6 Jul 2018 12:08:14 -0700 [thread overview]
Message-ID: <20180706190814.GB7259@bombadil.infradead.org> (raw)
In-Reply-To: <20180706182645.orttu3jjiox3v6kn@mwanda>
On Fri, Jul 06, 2018 at 09:26:46PM +0300, Dan Carpenter wrote:
> On Fri, Jul 06, 2018 at 10:51:30AM -0700, Matthew Wilcox wrote:
> > On Fri, Jul 06, 2018 at 08:21:01PM +0300, Dan Carpenter wrote:
> > > We need to unlock on this error path.
> > >
> > > Fixes: 29a6bfc32eb2 ("xarray: Track free entries in an XArray")
> > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > ---
> > >
> > > There "UINT_MAX + 1" is an integer overflow and is equal to zero but I
> > > don't know what was intended there.
> >
> > Ah. I didn't realise UINT_MAX was defined as ~0U. I had intended
> > UINT_MAX + 1UL. ie 0x10000000UL on 64-bit and 0 on 32-bit.
> >
>
> I will push a Smatch check so that the wrap around on 32 bit systems
> will generate a warning.
Do you mean "on 64-bit systems"? Because the code as-written was correct
on 32-bit systems and buggy on 64-bit systems.
I suppose generally, this is:
if (unsigned long == unsigned int + int)
where we can tell statically that the right hand side will wrap on 32-bit
systems and not on 64-bit systems.
next prev parent reply other threads:[~2018-07-06 19:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 17:21 [PATCH] xarray: unlock on error in xa_alloc() Dan Carpenter
2018-07-06 17:51 ` Matthew Wilcox
2018-07-06 18:26 ` Dan Carpenter
2018-07-06 19:08 ` Matthew Wilcox [this message]
2018-07-07 5:16 ` Dan Carpenter
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