Eric Lee / smarc-ti-linux-kernel

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Commit 8fa60ccc1cee10853e941a75c4359f9265ae0b59

Authored by Jiri Olsa
Committed by Greg Kroah-Hartman
1 parent a4a59e5833

perf/x86/intel/uncore: Make sure only uncore events are collected 

commit af91568e762d04931dcbdd6bef4655433d8b9418 upstream.

The uncore_collect_events functions assumes that event group
might contain only uncore events which is wrong, because it
might contain any type of events.

This bug leads to uncore framework touching 'not' uncore events,
which could end up all sorts of bugs.

One was triggered by Vince's perf fuzzer, when the uncore code
touched breakpoint event private event space as if it was uncore
event and caused BUG:

   BUG: unable to handle kernel paging request at ffffffff82822068
   IP: [<ffffffff81020338>] uncore_assign_events+0x188/0x250
   ...

The code in uncore_assign_events() function was looking for
event->hw.idx data while the event was initialized as a
breakpoint with different members in event->hw union.

This patch forces uncore_collect_events() to collect only uncore
events.

Reported-by: Vince Weaver <vince@deater.net>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Link: http://lkml.kernel.org/r/1418243031-20367-2-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 19 additions and 3 deletions Side-by-side Diff

arch/x86/kernel/cpu/perf_event_intel_uncore.c
Diff comments   View file @ 8fa60cc
... ... @@ -276,6 +276,17 @@
276 276 return box;
277 277 }
278 278  
  279 +/*
  280 + * Using uncore_pmu_event_init pmu event_init callback
  281 + * as a detection point for uncore events.
  282 + */
  283 +static int uncore_pmu_event_init(struct perf_event *event);
  284 +
  285 +static bool is_uncore_event(struct perf_event *event)
  286 +{
  287 + return event->pmu->event_init == uncore_pmu_event_init;
  288 +}
  289 +
279 290 static int
280 291 uncore_collect_events(struct intel_uncore_box *box, struct perf_event *leader, bool dogrp)
281 292 {
282 293  
... ... @@ -290,13 +301,18 @@
290 301 return -EINVAL;
291 302  
292 303 n = box->n_events;
293   - box->event_list[n] = leader;
294   - n++;
  304 +
  305 + if (is_uncore_event(leader)) {
  306 + box->event_list[n] = leader;
  307 + n++;
  308 + }
  309 +
295 310 if (!dogrp)
296 311 return n;
297 312  
298 313 list_for_each_entry(event, &leader->sibling_list, group_entry) {
299   - if (event->state <= PERF_EVENT_STATE_OFF)
  314 + if (!is_uncore_event(event) ||
  315 + event->state <= PERF_EVENT_STATE_OFF)
300 316 continue;
301 317  
302 318 if (n >= max_count)