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

From: Joseph Qi
Date: Sat Mar 02 2019 - 06:09:25 EST

Hi Adrian,

On 19/2/28 15:19, Adrian Hunter wrote:
> 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.
Have you sent out the patch officiallyï
I can't find it in the mail list.


>> 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>