Commit-ID: c499336cea8bbe15554c6fcea2138658c5395bfe Gitweb: http://git.kernel.org/tip/c499336cea8bbe15554c6fcea2138658c5395bfe Author: Kan Liang <[email protected]> AuthorDate: Tue, 15 Nov 2016 13:40:10 -0500 Committer: Ingo Molnar <[email protected]> CommitDate: Wed, 16 Nov 2016 09:46:35 +0100
perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client uncore IMC Vince Weaver reported the following bug when KASAN is enabled: [ 205.748005] BUG: KASAN: slab-out-of-bounds in snb_uncore_imc_event_del+0x6c/0xa0 at addr ffff8800caa43768 [ 205.758324] Read of size 8 by task perf_fuzzer/6618 It's caused by accessing box->event_list. For client IMC, there are no generic counters. It defines its own fixed free running counters. So event_list and n_events are unused. They can be removed safely, which fixes the bug. ( There's still the separate question of how uninitialized state snuck into this data structure - but that's a separate fix. ) Reported-by: Vince Weaver <[email protected]> Tested-by: Vince Weaver <[email protected]> Signed-off-by: Kan Liang <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Vince Weaver <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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; - } - } } int snb_pci2phy_map_init(int devid)
