linux-kernel - Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast removes address space '_

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 for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 11 Nov 2020 22:22:59 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     Serge Semin <fancer.lancer@...il.com>,
        kernel test robot <lkp@...el.com>, <kbuild-all@...ts.01.org>,
        <linux-kernel@...r.kernel.org>, <linux-mtd@...ts.infradead.org>
Subject: Re: drivers/mtd/maps/physmap-bt1-rom.c:78:18: sparse: sparse: cast
 removes address space '__iomem' of expression

On Tue, Nov 10, 2020 at 04:35:56PM +0100, Miquel Raynal wrote:
> Hi Serge,
> 
> Serge Semin <Sergey.Semin@...kalelectronics.ru> wrote on Tue, 10 Nov
> 2020 14:38:27 +0300:
> 
> > Hello Miquel,
> > 
> > A situation noted by the warning below won't cause any problem because
> > the casting is done to a non-dereferenced variable. It is utilized
> > as a pointer bias later in that function. Shall we just ignore the
> > warning or still fix it somehow?
> 

> Do you think the cast to a !__iomem value is mandatory here?

It's not mandatory to have the casting with no __iomem, but wouldn't
doing like this:
+ 	shift = (ssize_t __iomem)src & 0x3;
be looking weird? Really, is there a good way to somehow extract the first
two bits of a __iomem pointer without getting the sparse warning?

-Sergey

> 
> Perhaps if you find an elegant wait to avoid the warning it would be
> nice, otherwise I guess we'll let it aside as a false positive.
> 
> Cheers,
> Miquèl