perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client...
authorKan Liang <kan.liang@intel.com>
Tue, 15 Nov 2016 18:40:10 +0000 (13:40 -0500)
committerIngo Molnar <mingo@kernel.org>
Wed, 16 Nov 2016 08:46:35 +0000 (09:46 +0100)
commitc499336cea8bbe15554c6fcea2138658c5395bfe
tree7ae5419d8309f8e61633778f513b131b15eba3f4
parent864c2357ca898c6171fe5284f5ecc795c8ce27a8
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 <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: davej@codemonkey.org.uk
Cc: dvyukov@google.com
Cc: eranian@gmail.com
Link: http://lkml.kernel.org/r/1479235210-29090-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/events/intel/uncore_snb.c