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[sanitizer] do not acquire a global mutex in deadlock detector when dealing with Unlock (it is essentially a thread-local operation) 

llvm-svn: 202401
This commit is contained in:
Kostya Serebryany 2014-02-27 14:38:42 +00:00
parent a12923e265
commit 2ff42d98fa
3 changed files with 18 additions and 14 deletions
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27
compiler-rt/lib/sanitizer_common/sanitizer_deadlock_detector.h
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@ -48,16 +48,17 @@ class DeadlockDetectorTLS {
epoch_ = current_epoch;
}
uptr getEpoch() const { return epoch_; }
void addLock(uptr lock_id, uptr current_epoch) {
// Printf("addLock: %zx %zx\n", lock_id, current_epoch);
CHECK_EQ(epoch_, current_epoch);
CHECK(bv_.setBit(lock_id));
}
void removeLock(uptr lock_id, uptr current_epoch) {
void removeLock(uptr lock_id) {
// Printf("remLock: %zx %zx\n", lock_id, current_epoch);
CHECK_EQ(epoch_, current_epoch);
bv_.clearBit(lock_id); // May already be cleared due to epoch update.
CHECK(bv_.clearBit(lock_id));
}
const BV &getLocks(uptr current_epoch) const {
@ -75,7 +76,8 @@ class DeadlockDetectorTLS {
// and one DeadlockDetectorTLS object per evey thread.
// This class is not thread safe, all concurrent accesses should be guarded
// by an external lock.
// Not thread-safe, all accesses should be protected by an external lock.
// Most of the methods of this class are not thread-safe (i.e. should
// be protected by an external lock) unless explicitly told otherwise.
template <class BV>
class DeadlockDetector {
public:
@ -133,7 +135,7 @@ class DeadlockDetector {
}
// Handles the lock event, returns true if there is a cycle.
// FIXME: handle RW locks, recusive locks, etc.
// FIXME: handle RW locks, recursive locks, etc.
bool onLock(DeadlockDetectorTLS<BV> *dtls, uptr cur_node) {
ensureCurrentEpoch(dtls);
uptr cur_idx = nodeToIndex(cur_node);
@ -171,10 +173,11 @@ class DeadlockDetector {
return res;
}
// Handle the unlock event.
// Handle the unlock event. This operation is thread-safe
// as it only touches the dtls.
void onUnlock(DeadlockDetectorTLS<BV> *dtls, uptr node) {
ensureCurrentEpoch(dtls);
dtls->removeLock(nodeToIndex(node), current_epoch_);
if (dtls->getEpoch() == nodeToEpoch(node))
dtls->removeLock(nodeToIndexUnchecked(node));
}
bool isHeld(DeadlockDetectorTLS<BV> *dtls, uptr node) const {
@ -202,7 +205,7 @@ class DeadlockDetector {
void check_node(uptr node) const {
CHECK_GE(node, size());
CHECK_EQ(current_epoch_, node / size() * size());
CHECK_EQ(current_epoch_, nodeToEpoch(node));
}
uptr indexToNode(uptr idx) const {
@ -210,11 +213,15 @@ class DeadlockDetector {
return idx + current_epoch_;
}
uptr nodeToIndexUnchecked(uptr node) const { return node % size(); }
uptr nodeToIndex(uptr node) const {
check_node(node);
return node % size();
return nodeToIndexUnchecked(node);
}
uptr nodeToEpoch(uptr node) const { return node / size() * size(); }
uptr getAvailableNode(uptr data) {
uptr idx = available_nodes_.getAndClearFirstOne();
data_[idx] = data;

3
compiler-rt/lib/sanitizer_common/tests/sanitizer_deadlock_detector_test.cc
View File

@ -269,9 +269,8 @@ void RunMultipleEpochsTest() {
EXPECT_EQ(d.testOnlyGetEpoch(), 4 * d.size());
// Can not handle the locks from the previous epoch.
// The user should update the lock id.
// The caller should update the lock id.
EXPECT_DEATH(d.onLock(&dtls, l0), "CHECK failed.*current_epoch_");
EXPECT_DEATH(d.onUnlock(&dtls, l1), "CHECK failed.*current_epoch_");
}
TEST(DeadlockDetector, MultipleEpochsTest) {

2
compiler-rt/lib/tsan/rtl/tsan_rtl_mutex.cc
View File

@ -32,8 +32,6 @@ static void EnsureDeadlockDetectorID(Context *ctx, ThreadState *thr,
static void DDUnlock(Context *ctx, ThreadState *thr, SyncVar *s) {
if (!common_flags()->detect_deadlocks) return;
if (s->recursion != 0) return;
Lock lk(&ctx->dd_mtx);
EnsureDeadlockDetectorID(ctx, thr, s);
// Printf("T%d MutexUnlock: %zx; recursion %d\n", thr->tid,
// s->deadlock_detector_id, s->recursion);
ctx->dd.onUnlock(&thr->deadlock_detector_tls, s->deadlock_detector_id);