* kan.li...@intel.com <kan.li...@intel.com> wrote:
> From: Kan Liang <kan.li...@intel.com>
>
> A BUG was found by perf_fuzzer after enabled KASAN.
> [ 205.748005] BUG: KASAN: slab-out-of-bounds in
> snb_uncore_imc_event_del+0x6c/0xa0 at addr ffff8800caa43768
> Reported-by: Vince Weaver <vincent.wea...@maine.edu>
> Tested-by: Vince Weaver <vincent.wea...@maine.edu>
> Signed-off-by: Kan Liang <kan.li...@intel.com>
> ---
> arch/x86/events/intel/uncore_snb.c | 12 ------------
> 1 file changed, 12 deletions(-)
>
> diff --git a/arch/x86/events/intel/uncore_snb.c
> b/arch/x86/events/intel/uncore_snb.c
> index 81195cc..a3dcc12 100644
> --- a/arch/x86/events/intel/uncore_snb.c
> +++ b/arch/x86/events/intel/uncore_snb.c
> @@ -490,24 +490,12 @@ static int snb_uncore_imc_event_add(struct perf_event
> *event, int flags)
>
> snb_uncore_imc_event_start(event, 0);
>
> - box->n_events++;
> -
> return 0;
> }
>
> static void snb_uncore_imc_event_del(struct perf_event *event, int flags)
> {
> - struct intel_uncore_box *box = uncore_event_to_box(event);
> - int i;
> -
> snb_uncore_imc_event_stop(event, PERF_EF_UPDATE);
> -
> - for (i = 0; i < box->n_events; i++) {
> - if (event == box->event_list[i]) {
> - --box->n_events;
> - break;
> - }
> - }
I'll apply this fix - but could we please also make sure box->event_list[]
_always_ get initialized to a sane state?
If it had a proper zero initial value in box->n_events the bug would not have
triggered. So struct intel_uncore_box initialization appears to be sloppy,
and that should be looked at as well...
Thanks,
Ingo
