Re: [bug report][stable] perf probe: failed to add events

[Adrian Hunter]

On 28/02/19 4:07 AM, Joseph Qi wrote:
> Hi Adrian,
> 
> On 19/2/27 20:39, Adrian Hunter wrote:
>> Seems to be fixed by this:
>>
>> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> Date: Wed, 27 Feb 2019 05:35:25 +0200
>> Subject: [PATCH] perf probe: Fix getting the kernel map
>>
>> Since commit 4d99e4136580 ("perf machine: Workaround missing maps for x86
>> PTI entry trampolines"), perf tools has been creating more than one kernel
>> map, however 'perf probe' assumed there could be only one.
>>
>> Fix by using machine__kernel_map() to get the main kernel map.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> Fixes: 4d99e4136580 ("perf machine: Workaround missing maps for x86 PTI entry trampolines")
> 
> Below is my investigation result before, FYI.
> the first bad commit (v4.18 ~ v4.19):
> d83212d5dd67 kallsyms, x86: Export addresses of PTI entry trampolines

Yes we should add a fixes tag for that also.

> revert this commit on 4.19.0, it works.
> the first good commit again (v4.19 ~ v4.20):
> bf904d2762ee x86/pti/64: Remove the SYSCALL64 entry trampoline
> backported this commit as well as the related commit 98f05b5138f0 on
> v4.19.24, it works.
> 
> And I've tested your fix on v4.19.24, it also works.
> Tested-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
>