[SRU][Bionic][Cosmic][PATCH 1/1] powerpc/livepatch: Implement reliable stack tracing for the consistency model

[Joseph Salisbury]

On 06/07/2018 01:37 PM, Khaled Elmously wrote:
> On 2018-06-05 11:52:15 , Joseph Salisbury wrote:
>> On 06/04/2018 10:11 PM, Michael Ellerman wrote:
>>> Joseph Salisbury <joseph.salisbury at canonical.com> writes:
>>>> diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
>>>> index d534ed901538..26a50603177c 100644
>>>> --- a/arch/powerpc/kernel/stacktrace.c
>>>> +++ b/arch/powerpc/kernel/stacktrace.c
>>>> @@ -76,3 +81,115 @@ save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
>>>>  	save_context_stack(trace, regs->gpr[1], current, 0);
>>>>  }
>>>>  EXPORT_SYMBOL_GPL(save_stack_trace_regs);
>>>> +
>>>> +#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
>>>> +int
>>>> +save_stack_trace_tsk_reliable(struct task_struct *tsk,
>>>> +				struct stack_trace *trace)
>>>> +{
>>> ...
>>>> +		/*
>>>> +		 * Mark stacktraces with kretprobed functions on them
>>>> +		 * as unreliable.
>>>> +		 */
>>>> +		if (ip == (unsigned long)kretprobe_trampoline)
>>>> +			return 1;
>>> You may also want:
>>>
>>> 5e3f0d15ae5f ("powerpc/livepatch: Fix build error with kprobes disabled.")
>>>
>>> cheers
>> Thanks for the feedback, Michael.  Would it be possible for you to post
>> this comment to the bug?  That way we can get feedback from the original
>> bug reporter and IBM.
>>
>>
>> Thanks,
>>
>>
>> Joe
> Joe, I did not apply this patch as it is not clear to me if a V2 is on the way or if it needs more work. Please advise.
>
> Thanks
>
> Khalid
I don't plan on sending a V2.  IBM tested what is in this SRU request
and it was confirmed to fix the bug for them.  I would say apply what is
in this request.

Michael, it's probably best to open a new bug if you believe additional
commits are needed.

>
>>
>>
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