aboutsummaryrefslogtreecommitdiffstats
path: root/lib/sanitizer_common/sanitizer_deadlock_detector1.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/sanitizer_common/sanitizer_deadlock_detector1.cpp')
-rw-r--r--lib/sanitizer_common/sanitizer_deadlock_detector1.cpp194
1 files changed, 194 insertions, 0 deletions
diff --git a/lib/sanitizer_common/sanitizer_deadlock_detector1.cpp b/lib/sanitizer_common/sanitizer_deadlock_detector1.cpp
new file mode 100644
index 000000000000..d4a325bea4b2
--- /dev/null
+++ b/lib/sanitizer_common/sanitizer_deadlock_detector1.cpp
@@ -0,0 +1,194 @@
+//===-- sanitizer_deadlock_detector1.cpp ----------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Deadlock detector implementation based on NxN adjacency bit matrix.
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_deadlock_detector_interface.h"
+#include "sanitizer_deadlock_detector.h"
+#include "sanitizer_allocator_internal.h"
+#include "sanitizer_placement_new.h"
+#include "sanitizer_mutex.h"
+
+#if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1
+
+namespace __sanitizer {
+
+typedef TwoLevelBitVector<> DDBV; // DeadlockDetector's bit vector.
+
+struct DDPhysicalThread {
+};
+
+struct DDLogicalThread {
+ u64 ctx;
+ DeadlockDetectorTLS<DDBV> dd;
+ DDReport rep;
+ bool report_pending;
+};
+
+struct DD : public DDetector {
+ SpinMutex mtx;
+ DeadlockDetector<DDBV> dd;
+ DDFlags flags;
+
+ explicit DD(const DDFlags *flags);
+
+ DDPhysicalThread *CreatePhysicalThread() override;
+ void DestroyPhysicalThread(DDPhysicalThread *pt) override;
+
+ DDLogicalThread *CreateLogicalThread(u64 ctx) override;
+ void DestroyLogicalThread(DDLogicalThread *lt) override;
+
+ void MutexInit(DDCallback *cb, DDMutex *m) override;
+ void MutexBeforeLock(DDCallback *cb, DDMutex *m, bool wlock) override;
+ void MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock,
+ bool trylock) override;
+ void MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) override;
+ void MutexDestroy(DDCallback *cb, DDMutex *m) override;
+
+ DDReport *GetReport(DDCallback *cb) override;
+
+ void MutexEnsureID(DDLogicalThread *lt, DDMutex *m);
+ void ReportDeadlock(DDCallback *cb, DDMutex *m);
+};
+
+DDetector *DDetector::Create(const DDFlags *flags) {
+ (void)flags;
+ void *mem = MmapOrDie(sizeof(DD), "deadlock detector");
+ return new(mem) DD(flags);
+}
+
+DD::DD(const DDFlags *flags)
+ : flags(*flags) {
+ dd.clear();
+}
+
+DDPhysicalThread* DD::CreatePhysicalThread() {
+ return nullptr;
+}
+
+void DD::DestroyPhysicalThread(DDPhysicalThread *pt) {
+}
+
+DDLogicalThread* DD::CreateLogicalThread(u64 ctx) {
+ DDLogicalThread *lt = (DDLogicalThread*)InternalAlloc(sizeof(*lt));
+ lt->ctx = ctx;
+ lt->dd.clear();
+ lt->report_pending = false;
+ return lt;
+}
+
+void DD::DestroyLogicalThread(DDLogicalThread *lt) {
+ lt->~DDLogicalThread();
+ InternalFree(lt);
+}
+
+void DD::MutexInit(DDCallback *cb, DDMutex *m) {
+ m->id = 0;
+ m->stk = cb->Unwind();
+}
+
+void DD::MutexEnsureID(DDLogicalThread *lt, DDMutex *m) {
+ if (!dd.nodeBelongsToCurrentEpoch(m->id))
+ m->id = dd.newNode(reinterpret_cast<uptr>(m));
+ dd.ensureCurrentEpoch(&lt->dd);
+}
+
+void DD::MutexBeforeLock(DDCallback *cb,
+ DDMutex *m, bool wlock) {
+ DDLogicalThread *lt = cb->lt;
+ if (lt->dd.empty()) return; // This will be the first lock held by lt.
+ if (dd.hasAllEdges(&lt->dd, m->id)) return; // We already have all edges.
+ SpinMutexLock lk(&mtx);
+ MutexEnsureID(lt, m);
+ if (dd.isHeld(&lt->dd, m->id))
+ return; // FIXME: allow this only for recursive locks.
+ if (dd.onLockBefore(&lt->dd, m->id)) {
+ // Actually add this edge now so that we have all the stack traces.
+ dd.addEdges(&lt->dd, m->id, cb->Unwind(), cb->UniqueTid());
+ ReportDeadlock(cb, m);
+ }
+}
+
+void DD::ReportDeadlock(DDCallback *cb, DDMutex *m) {
+ DDLogicalThread *lt = cb->lt;
+ uptr path[20];
+ uptr len = dd.findPathToLock(&lt->dd, m->id, path, ARRAY_SIZE(path));
+ if (len == 0U) {
+ // A cycle of 20+ locks? Well, that's a bit odd...
+ Printf("WARNING: too long mutex cycle found\n");
+ return;
+ }
+ CHECK_EQ(m->id, path[0]);
+ lt->report_pending = true;
+ len = Min<uptr>(len, DDReport::kMaxLoopSize);
+ DDReport *rep = &lt->rep;
+ rep->n = len;
+ for (uptr i = 0; i < len; i++) {
+ uptr from = path[i];
+ uptr to = path[(i + 1) % len];
+ DDMutex *m0 = (DDMutex*)dd.getData(from);
+ DDMutex *m1 = (DDMutex*)dd.getData(to);
+
+ u32 stk_from = -1U, stk_to = -1U;
+ int unique_tid = 0;
+ dd.findEdge(from, to, &stk_from, &stk_to, &unique_tid);
+ // Printf("Edge: %zd=>%zd: %u/%u T%d\n", from, to, stk_from, stk_to,
+ // unique_tid);
+ rep->loop[i].thr_ctx = unique_tid;
+ rep->loop[i].mtx_ctx0 = m0->ctx;
+ rep->loop[i].mtx_ctx1 = m1->ctx;
+ rep->loop[i].stk[0] = stk_to;
+ rep->loop[i].stk[1] = stk_from;
+ }
+}
+
+void DD::MutexAfterLock(DDCallback *cb, DDMutex *m, bool wlock, bool trylock) {
+ DDLogicalThread *lt = cb->lt;
+ u32 stk = 0;
+ if (flags.second_deadlock_stack)
+ stk = cb->Unwind();
+ // Printf("T%p MutexLock: %zx stk %u\n", lt, m->id, stk);
+ if (dd.onFirstLock(&lt->dd, m->id, stk))
+ return;
+ if (dd.onLockFast(&lt->dd, m->id, stk))
+ return;
+
+ SpinMutexLock lk(&mtx);
+ MutexEnsureID(lt, m);
+ if (wlock) // Only a recursive rlock may be held.
+ CHECK(!dd.isHeld(&lt->dd, m->id));
+ if (!trylock)
+ dd.addEdges(&lt->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
+ dd.onLockAfter(&lt->dd, m->id, stk);
+}
+
+void DD::MutexBeforeUnlock(DDCallback *cb, DDMutex *m, bool wlock) {
+ // Printf("T%p MutexUnLock: %zx\n", cb->lt, m->id);
+ dd.onUnlock(&cb->lt->dd, m->id);
+}
+
+void DD::MutexDestroy(DDCallback *cb,
+ DDMutex *m) {
+ if (!m->id) return;
+ SpinMutexLock lk(&mtx);
+ if (dd.nodeBelongsToCurrentEpoch(m->id))
+ dd.removeNode(m->id);
+ m->id = 0;
+}
+
+DDReport *DD::GetReport(DDCallback *cb) {
+ if (!cb->lt->report_pending)
+ return nullptr;
+ cb->lt->report_pending = false;
+ return &cb->lt->rep;
+}
+
+} // namespace __sanitizer
+#endif // #if SANITIZER_DEADLOCK_DETECTOR_VERSION == 1