Re: [RFC PATCH v1 3/4] arm64: Detect FTRACE cases that make the stack trace unreliable

Madhavan T. Venkataraman
2021-04-01T18:06:41Z

On 4/1/21 9:27 AM, Mark Brown wrote:
> On Tue, Mar 30, 2021 at 02:09:54PM -0500, madvenka@linux.microsoft.com wrote:
>
>> + * FTRACE trampolines.
>> + */
>> +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
>> + { (unsigned long) &ftrace_graph_call, 0 },
>> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
>> + { (unsigned long) ftrace_graph_caller, 0 },
>> + { (unsigned long) return_to_handler, 0 },
>> +#endif
>> +#endif
>
> It's weird that we take the address of ftrace_graph_call but not the
> other functions - we should be consistent or explain why. It'd probably
> also look nicer to not nest the ifdefs, the dependencies in Kconfig will
> ensure we only get things when we should.
>

Sorry. I forgot to respond to the nested ifdef comment. I will fix that.

Thanks!

Madhavan