commit 5ef7020490126d868b10e8d40cdd2963c51eaa6c
author Mathieu Chartier <mathieuc@google.com> Thu Jun 29 10:45:10 2017 -0700
committer Mathieu Chartier <mathieuc@google.com> Thu Jun 29 10:50:10 2017 -0700
tree a0bf3d5800708843e4e492fd24b58e0db1fe9103
parent fe9a4f061841a3c597aac6817a47c799c54fcad7

Handle spurious wakeups in VerifyClass

Spurious wakeups in VerifyClass can cause the class status to be
the same as the old status. Relax the check to be >= to handle this.

Adding a regression test is infeasible since it is a hard to get a
thread in the "somebody else verifying" loop.

Test: test-art-host
Bug: 62912904
Change-Id: I308a395220507a875bb2fbf0800a14fabb434fda

runtime/class_linker.cc

diff --git a/runtime/class_linker.cc b/runtime/class_linker.cc
index 928645a..10e0bd2 100644
--- a/runtime/class_linker.cc
+++ b/runtime/class_linker.cc
@@ -4064,7 +4064,10 @@
     while (old_status == mirror::Class::kStatusVerifying ||
         old_status == mirror::Class::kStatusVerifyingAtRuntime) {
       lock.WaitIgnoringInterrupts();
-      CHECK(klass->IsErroneous() || (klass->GetStatus() > old_status))
+      // WaitIgnoringInterrupts can still receive an interrupt and return early, in this
+      // case we may see the same status again. b/62912904. This is why the check is
+      // greater or equal.
+      CHECK(klass->IsErroneous() || (klass->GetStatus() >= old_status))
           << "Class '" << klass->PrettyClass()
           << "' performed an illegal verification state transition from " << old_status
           << " to " << klass->GetStatus();