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Date:   Sat, 10 Oct 2020 12:55:20 -0500
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc:     Xiaoming Ni <nixiaoming@huawei.com>, dima@arista.com,
        will@kernel.org, akpm@linux-foundation.org,
        christian.brauner@ubuntu.com, viro@zeniv.linux.org.uk,
        ldufour@linux.ibm.com, amanieu@gmail.com, walken@google.com,
        ben.dooks@codethink.co.uk, tglx@linutronix.de,
        bigeasy@linutronix.de, mingo@kernel.org,
        vincent.whitchurch@axis.com, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, wangle6@huawei.com,
        luohaizheng@huawei.com
Subject: Re: [PATCH] arm:traps: Don't print stack or raw PC/LR values in
 backtraces
Message-ID: <20201010175520.fczgnp66ey2vghkr@treble>
References: <20201009075957.110017-1-nixiaoming@huawei.com>
 <20201009080849.GM1551@shell.armlinux.org.uk>
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On Fri, Oct 09, 2020 at 09:08:50AM +0100, Russell King - ARM Linux admin wrote:
> On Fri, Oct 09, 2020 at 03:59:57PM +0800, Xiaoming Ni wrote:
> > Printing raw pointer values in backtraces has potential security
> > implications and are of questionable value anyway.
> > 
> > This patch follows x86 and arm64's lead and removes the "Exception stack:"
> > dump from kernel backtraces:
> > 	commit a25ffd3a6302a6 ("arm64: traps: Don't print stack or raw
> > 	 PC/LR values in backtraces")
> > 	commit 0ee1dd9f5e7eae ("x86/dumpstack: Remove raw stack dump")
> > 	commit bb5e5ce545f203 ("x86/dumpstack: Remove kernel text
> > 	 addresses from stack dump")
> > 
> > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> 
> I am really not happy about this - it hurts at least my ability to
> debug the kernel when people post oopses to the mailing list. If
> people wish to make the kernel harder to debug, and are prepared
> to be told "your kernel is undebuggable" then this patch is fine.

At least on x86 we've had this for four years now, without any apparent
harm to debugability.  scripts/faddr2line helps.

-- 
Josh