• Ravi Bangoria's avatar
    powerpc/perf: Fix oops when grouping different pmu events · 5aa04b3e
    Ravi Bangoria authored
    When user tries to group imc (In-Memory Collections) event with
    normal event, (sometime) kernel crashes with following log:
    
        Faulting instruction address: 0x00000000
        [link register   ] c00000000010ce88 power_check_constraints+0x128/0x980
        ...
        c00000000010e238 power_pmu_event_init+0x268/0x6f0
        c0000000002dc60c perf_try_init_event+0xdc/0x1a0
        c0000000002dce88 perf_event_alloc+0x7b8/0xac0
        c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
        c00000000000b004 system_call+0x38/0xe0
    
    'event_base' field of 'struct hw_perf_event' is used as flags for
    normal hw events and used as memory address for imc events. While
    grouping these two types of events, collect_events() tries to
    interpret imc 'event_base' as a flag, which causes a corruption
    resulting in a crash.
    
    Consider only those events which belongs to 'perf_hw_context' in
    collect_events().
    Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
    Reviewed-By: default avatarMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
    Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
    5aa04b3e
core-book3s.c 56.1 KB