linux-kernel - Re: [PATCH] i2c: s3c2410: Properly handle interrupts of number 0

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]

Date:   Fri, 2 Mar 2018 13:46:47 +0100
From:   Wolfram Sang <wsa@...-dreams.de>
To:     Russell King - ARM Linux <linux@...linux.org.uk>
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Ben Dooks <ben-linux@...ff.org>,
        Dan Carpenter <dan.carpenter@...cle.com>
Subject: Re: [PATCH] i2c: s3c2410: Properly handle interrupts of number 0


So, maybe some words why I accepted this patch.

On Fri, Mar 02, 2018 at 11:19:31AM +0000, Russell King - ARM Linux wrote:
> On Thu, Mar 01, 2018 at 09:34:44PM +0100, Krzysztof Kozlowski wrote:
> > Interrupt number 0 (returned by platform_get_irq()) might be a valid IRQ
> > so do not treat it as an error.  If interrupt 0 was configured, the driver
> > would exit the probe early, before finishing initialization, but with
> > 0-exit status.
> 
> The official position (as stated by Linus) is that interrupt zero is
> not a valid interrupt for peripheral drivers (it may be valid within
> architecture code for things like the x86 PIT, but nothing else.)

I am aware of that situation and I totally agree with the reasoning.

> You need to number your platform interrupts from one rather than zero.

Ack.

> Note that there have been patches proposed to make platform_get_irq()
> return an error rather than returning a value of zero, so changing
> the driver in this way is not a good idea.

I'd much agree to such an approach, yet I didn't see it coming along so
far for years(?) now.

The reason I applied this patch is consistency with the current
interface. The code is wrong with the way platform_get_irq right now
works. This is independent of platform_get_irq should work, I thought.
This needs to be fixed in a seperate series. This patch will not harm
that transition.


Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)