x86, perf: Fix NULL deref on not assigned x86_pmu
x86, perf: Fix NULL deref on not assigned x86_pmu

In case of not assigned x86_pmu and software events NULL dereference may
being hit via x86_pmu::schedule_events method.

Fix it by checking if x86_pmu is initialized at all.

Signed-off-by: Cyrill Gorcunov <7a1ea01eee6961eb1e372e3508c2670446d086f4@openvz.org>
Cc: Lin Ming <d6f051473f553588884d51874952f6fb19ae8261@intel.com>
Cc: Arnaldo Carvalho de Melo <293abb6b76d7791c0732cc517d38c4b5c734b87f@redhat.com>
Cc: Stephane Eranian <f199ae9781930a5b94b284ca2f471140752002a7@google.com>
Cc: Robert Richter <22a70fd9773e4de05b12c05075e9bcd605577f4d@amd.com>
Cc: Frederic Weisbecker <e8a1bf9163cb25e93cfd6540f223b3872ea7ee55@gmail.com>
Cc: Peter Zijlstra <3fddac958924aef220f202ca567388ddab3f14a8@infradead.org>
LKML-Reference: <f119196386fb21a6a22426ac1ff4c520dd5edd8d@lenovo>
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@elte.hu>

TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs