Hi, Sorry for the late reply.
On Tue, Nov 07, 2017 at 08:50:53PM +0800, Huang Rui wrote: > On Fri, Nov 03, 2017 at 11:33:56AM +0000, Mark Rutland wrote: > > As a heads-up, I believe that arch/x86/events/amd/power.c is currently > > missing initialisation of pmu::module, which could result in problems > > when the module is unloaded. > > > > We've just spotted a similar problem in a couple of ARM PMUs, and AFAICT > > the AMD power PMU is the only other PMU affected. > > > > Other modular PMUs all initialise this to THIS_MODULE prior to calling > > perf_pmu_register(). > > Thanks to let me know. I have dived into pmu for quite a while. Could you > please share more information or forward related mail thread, so that I can > repro this issue in my side. :-) Unfortunately, in the other thread, we only noticed that this was missing, and weren't entirely sure of the issue. IIUC, without pmu::module initialised, the module can be freed immediately after an event is created by perf_init_event(), while the event is still around, with dangling pointers to the PMU (and other data structures owned by the module that have been freed). Thanks, Mark.