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From: linux@armlinux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: Stop printing the virtual memory layout
Date: Thu, 18 Jan 2018 20:20:53 +0000	[thread overview]
Message-ID: <20180118202053.GR17719@n2100.armlinux.org.uk> (raw)
In-Reply-To: <94d6b5c8-07c4-32b5-9746-646b0021d2e9@gmail.com>

On Thu, Jan 18, 2018 at 12:01:31PM -0800, Florian Fainelli wrote:
> On 12/19/2017 11:28 AM, Laura Abbott wrote:
> > Printing kernel addresses should be done in limited circumstances, mostly
> > for debugging purposes. Printing out the virtual memory layout at every
> > kernel bootup doesn't really fall into this category so delete the prints.
> > There are other ways to get the same information.
> 
> This really has some value when debugging systems, could we possibly
> just hide that behind an appropriate configuration option instead of
> completely removing this?

I've already ended up having to revert the vsprintf() change nobbling
%p for that very reason when debugging the BPF code.  It's easier to
do that while debugging than remember about the %px thing - and lets
face it, probably less error prone if it leaks out.

Otherwise we'll just end up with everyone spelling %p as %px in their
debug statements... or using %lx and casting to unsigned long.

So yes, I do think a Kconfig option (defaulting to obscuring kernel
addresses of course) would have been very sensible for this.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up
According to speedtest.net: 8.21Mbps down 510kbps up

      reply	other threads:[~2018-01-18 20:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-19 19:28 [PATCH] arm64: Stop printing the virtual memory layout Laura Abbott
2017-12-19 21:04 ` Kees Cook
2017-12-19 22:18   ` Laura Abbott
2018-01-09 23:02   ` Kees Cook
2018-01-15 18:18     ` Catalin Marinas
2018-01-15 20:00       ` Kees Cook
2018-01-18 20:01 ` Florian Fainelli
2018-01-18 20:20   ` Russell King - ARM Linux [this message]

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