[PATCH 1/2] ftrace: disable preemption on the testing of recursion
yun.wang at linux.alibaba.com
Tue Oct 12 18:46:42 PDT 2021
On 2021/10/12 下午8:17, Steven Rostedt wrote:
> On Tue, 12 Oct 2021 13:40:08 +0800
> 王贇 <yun.wang at linux.alibaba.com> wrote:
>> @@ -52,11 +52,6 @@ static void notrace klp_ftrace_handler(unsigned long ip,
>> bit = ftrace_test_recursion_trylock(ip, parent_ip);
>> if (WARN_ON_ONCE(bit < 0))
>> - /*
>> - * A variant of synchronize_rcu() is used to allow patching functions
>> - * where RCU is not watching, see klp_synchronize_transition().
>> - */
> I have to take a deeper look at this patch set, but do not remove this
> comment, as it explains the protection here, that is not obvious with the
> changes you made.
Will keep that in v2.
> -- Steve
>> - preempt_disable_notrace();
>> func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
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