Messages in this thread | | | Subject | Re: [bug report][stable] perf probe: failed to add events | From | Joseph Qi <> | Date | Tue, 26 Feb 2019 20:32:34 +0800 |
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On 19/2/26 17:05, Greg KH wrote: > On Tue, Feb 26, 2019 at 03:31:14PM +0800, Joseph Qi wrote: >> Hi, >> >> I'm using kernel v4.19.24 and have found that there is an issue when >> using perf probe to define a new dynamic tracepoint. >> >> $ perf probe -a handle_mm_fault >> Failed to write event: Numerical result out of range >> Error: Failed to add events. >> >> I've also tried kernel v4.20, and it can pass. > > Ick, has this ever worked on the 4.19 stable tree? If so, any chance > you can run 'git bisect' to find the offending commit? > From my test, v4.19.0 also has this issue. Bisect locates that it is introduced by commit bf904d2762ee "x86/pti/64: Remove the SYSCALL64 entry trampoline".
Thanks, Joseph
>> So I've bisected and finally found the first good commit is: >> bf904d2762ee x86/pti/64: Remove the SYSCALL64 entry trampoline >> which is based on another commit: >> 98f05b5138f0 Use the TSS sp2 slot for SYSCALL/SYSRET scratch space >> >> Once I've backpoted these two commits into 4.19.24, the above case can >> pass, though I'm not sure how it is fixed. >> So is there any plan to let them go into stable as well? > > If they are needed, I'll gladly queue them up, but this feels like > something might have broken, so it should be easier to just revert the > offending commit instead. > > Andy, any ideas? > > thanks, > > greg k-h >
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