linux-kernel - Re: [PATCH v2] lib_backtrace: fix kernel text address leak

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Message-ID: <20171106171401.4h546bbvdon45or2@treble>
Date:   Mon, 6 Nov 2017 11:14:01 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     "Liu, Changcheng" <changcheng.liu@...el.com>
Cc:     Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] lib_backtrace: fix kernel text address leak

On Tue, Nov 07, 2017 at 12:56:48AM +0800, Liu, Changcheng wrote:
> Don't leak idle function address in NMI backtrace.
> 
> Signed-off-by: Liu Changcheng <changcheng.liu@...el.com>
> 
> diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c
> index 46e4c749..61a6b5a 100644
> --- a/lib/nmi_backtrace.c
> +++ b/lib/nmi_backtrace.c
> @@ -93,8 +93,8 @@ bool nmi_cpu_backtrace(struct pt_regs *regs)
>  	if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) {
>  		arch_spin_lock(&lock);
>  		if (regs && cpu_in_idle(instruction_pointer(regs))) {
> -			pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n",
> -				cpu, instruction_pointer(regs));
> +			pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n",
> +				cpu, (void *)instruction_pointer(regs));
>  		} else {
>  			pr_warn("NMI backtrace for cpu %d\n", cpu);
>  			if (regs)

Sorry, I had a typo in my suggestion.  The subject prefix should be:
"nmi_backtrace" instead of "lib_backtrace".

Also, when posting a followup patch, please remove the "Re: " from the
subject so that it's clear that it's a new patch, and not a comment for
the old one.

Otherwise it looks great to me.  Thanks!

-- 
Josh