On Thu, Mar 14, 2019 at 02:10:14PM -0700, Guenter Roeck wrote:

On Tue, Mar 05, 2019 at 10:23:15PM +0100, Peter Zijlstra (Intel) wrote:

...

The cpuc data structure allocation is different between fake and real cpuc's; use the same code to init/free both.

Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Thomas Gleixner tglx@linutronix.de

With allmodconfig-CONFIG_CPU_SUP_INTEL, this patch results in:

In file included from arch/x86/events/amd/core.c:8:0: arch/x86/events/amd/../perf_event.h:1036:45: warning: ‘struct cpu_hw_event’ declared inside parameter list will not be visible outside of this definition or declaration static inline int intel_cpuc_prepare(struct cpu_hw_event *cpuc, int cpu) ^~~~~~~~~~~~ arch/x86/events/amd/../perf_event.h:1041:45: warning: ‘struct cpu_hw_event’ declared inside parameter list will not be visible outside of this definition or declaration static inline void intel_cpuc_finish(struct cpu_hw_event *cpuc) ^~~~~~~~~~~~

With -Werror, this is fatal, and I think it may be buggy (should it be cpu_hw_events) ?

Yep it should be. Won't result in a bug though, an unused pointer is an unused poiner, no matter what known or unknown type it points to.

The patch has been applied to stable releases. Any idea, anyone, why this is the case ? It doesn't look like a bug fix to me, and reverting it from v4.14.106 didn't seem to have a negative impact.

Reverting just this one patch will make your kernel go boom when you run on a skylake or more recent Intel cpu, have updated your microcode and do:

echo 0 > /sys/bus/event_source/devices/cpu/allow_tsx_force_abort

And then try and create perf events. See also commit:

400816f60c54 ("perf/x86/intel: Implement support for TSX Force Abort")

--- Subject: perf/x86: Fixup typo in stub functions

Guenter reported a build warning for CONFIG_CPU_SUP_INTEL=n. While harmless (an unsed pointer is an unused pointer, no matter the type) it needs fixing.

Reported-by: Guenter Roeck linux@roeck-us.net Fixes: d01b1f96a82e ("perf/x86/intel: Make cpuc allocations consistent") Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org --- arch/x86/events/perf_event.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index b04ae6c8775e..a75955741c50 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1033,12 +1033,12 @@ static inline int intel_pmu_init(void) return 0; }

-static inline int intel_cpuc_prepare(struct cpu_hw_event *cpuc, int cpu) +static inline int intel_cpuc_prepare(struct cpu_hw_events *cpuc, int cpu) { return 0; }

-static inline void intel_cpuc_finish(struct cpu_hw_event *cpuc) +static inline void intel_cpuc_finish(struct cpu_hw_events *cpuc) { }