linux-kernel - Re: [PATCH] PCI: imx6: Fix wrong check in imx6_pcie_attach

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:   Tue, 13 Sep 2022 08:46:06 +0100
From:   "Russell King (Oracle)" <linux@...linux.org.uk>
To:     Lucas Stach <l.stach@...gutronix.de>
Cc:     Tang Bin <tangbin@...s.chinamobile.com>, hongxing.zhu@....com,
        lorenzo.pieralisi@....com, robh@...nel.org, kw@...ux.com,
        shawnguo@...nel.org, bhelgaas@...gle.com, s.hauer@...gutronix.de,
        kernel@...gutronix.de, festevam@...il.com, linux-imx@....com,
        linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] PCI: imx6: Fix wrong check in imx6_pcie_attach_pd()

On Tue, Sep 13, 2022 at 09:39:03AM +0200, Lucas Stach wrote:
> Am Dienstag, dem 13.09.2022 um 14:59 +0800 schrieb Tang Bin:
> > In the function imx6_pcie_attach_pd(),
> > dev_pm_domain_attach_by_name() may return NULL in some cases,
> > so IS_ERR() doesn't meet the requirements. Thus fix it.
> > 
> I don't like this added complexity in the driver. IHMO if there is a
> real issue, dev_pm_domain_attach_by_name() should just return a error
> code, instead of NULL.

You've fallen into the trap that Tang Bin laid. It returns an error
code for all cases where an error has happened. It returns NULL only
when the device does not require a power domain. So, a NULL return is
*not* an error condition, but merely an indication that "this device
does not require this power domain".

Mechanical changes like this are really quite harmful to the kernel.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!