From: Jim Meyering <meyering@fb.com>
Date: Wed, 25 Jun 2014 23:47:55 +0000 (-0700)
Subject: folly: futexWaitUntilImpl: avoid abort triggered via tao/queues tests
X-Git-Tag: v0.22.0~491
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b27ed0f6ed5325abcc368f8433fc92fb3c9dc77a;p=folly.git

folly: futexWaitUntilImpl: avoid abort triggered via tao/queues tests

Summary:
* folly/test/DeterministicSchedule.cpp (folly): Tao/queues tests exposed
an unhandled case in this code: when (futex->data == expected) happens,
we would call futexErrnoToFutexResult with a futexErrno value of 0,
which would cause an abort (unhandled valued in switch).
Here's a stack trace from the abort: https://phabricator.fb.com/P12558008
showing the invalid futexErrno value in frame #4.

Test Plan:
fbconfig -r --platform-all=gcc-4.8.1-glibc-2.17 --sanitize=address tao/queues:TimeoutWorkQueueTests
_bin/tao/queues/WorkQueueTests -fbunit_test_regexp '^mt\_stress\_deterministic$'

Reviewed By: mssarang@fb.com

FB internal diff: D1404572

Tasks: 4494871
---

diff --git a/folly/test/DeterministicSchedule.cpp b/folly/test/DeterministicSchedule.cpp
index 4da48443..f4c355e0 100644
--- a/folly/test/DeterministicSchedule.cpp
+++ b/folly/test/DeterministicSchedule.cpp
@@ -294,6 +294,8 @@ FutexResult futexWaitUntilImpl(Futex<DeterministicAtomic>* futex,
         break;
       }
     }
+  } else {
+    futexErrno = EWOULDBLOCK;
   }
   futexLock.unlock();
   DeterministicSchedule::afterSharedAccess();