linux-kernel - Re: [PATCH] staging: unisys: use common return path

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <565DC7D0.3000307@unisys.com>
Date:	Tue, 1 Dec 2015 11:16:16 -0500
From:	Ben Romer <benjamin.romer@...sys.com>
To:	Dan Carpenter <dan.carpenter@...cle.com>
CC:	Sudip Mukherjee <sudipm.mukherjee@...il.com>,
	<devel@...verdev.osuosl.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	<sparmaintainer@...sys.com>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: unisys: use common return path

On 12/01/2015 10:57 AM, Dan Carpenter wrote:
> What I meant was that I'm generally opposed to "common exit paths".
> Mixing all the exit paths together often makes the code more complicated
> and leads to errors.  That makes sense from a common sense perspective
> that doing many things is more difficult than doing one thing?  Anyway
> it's easy enough to verify empirically that this style is bug prone.
>
> On the other hand there are times where all exit paths need to unlock or
> to free a variable and in those cases using a common exit path makes
> sense.  Just don't standardize on "Every function should only have a
> single return".
>

That works for me. Mainly my issue with it is that I've spent a lot of 
time trying to eliminate "goto Away" code from the drivers, so I'd 
rather not put any back if possible.

>>
>> If we *have* to change it
>
> I don't think we have to change it at all.  Using direct returns makes
> finding locking bugs easier for static checkers.
>

That's true, and I think the code is fine as it is.

>> 		spin_unlock_irqrestore(&devdata->priv_lock, flags);
>
> This is a bug.
>

Indeed, but I'd rather not have any of these changes made anyway. This 
function isn't broken so it doesn't need to be fixed.

-- Ben
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/