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

From: Josh Poimboeuf
Date: Mon Nov 06 2017 - 12:14:07 EST


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@xxxxxxxxx>
>
> 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