Commit ede271b0 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Thomas Gleixner

perf/x86/intel: Fix memory corruption

Through:

  validate_event()
    x86_pmu.get_event_constraints(.idx=-1)
      tfa_get_event_constraints()
        dyn_constraint()

cpuc->constraint_list[-1] is used, which is an obvious out-of-bound access.

In this case, simply skip the TFA constraint code, there is no event
constraint with just PMC3, therefore the code will never result in the
empty set.

Fixes: 400816f6 ("perf/x86/intel: Implement support for TSX Force Abort")
Reported-by: default avatarTony Jones <tonyj@suse.com>
Reported-by: default avatar"DSouza, Nelson" <nelson.dsouza@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarTony Jones <tonyj@suse.com>
Tested-by: default avatar"DSouza, Nelson" <nelson.dsouza@intel.com>
Cc: eranian@google.com
Cc: jolsa@redhat.com
Cc: stable@kernel.org
Link: https://lkml.kernel.org/r/20190314130705.441549378@infradead.org
parent f261c4e5
......@@ -3410,7 +3410,7 @@ tfa_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
/*
* Without TFA we must not use PMC3.
*/
if (!allow_tsx_force_abort && test_bit(3, c->idxmsk)) {
if (!allow_tsx_force_abort && test_bit(3, c->idxmsk) && idx >= 0) {
c = dyn_constraint(cpuc, c, idx);
c->idxmsk64 &= ~(1ULL << 3);
c->weight--;
......
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