1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
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(<->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(<->dd, m->id)) return; // We already have all edges.
SpinMutexLock lk(&mtx);
MutexEnsureID(lt, m);
if (dd.isHeld(<->dd, m->id))
return; // FIXME: allow this only for recursive locks.
if (dd.onLockBefore(<->dd, m->id)) {
// Actually add this edge now so that we have all the stack traces.
dd.addEdges(<->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(<->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 = <->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(<->dd, m->id, stk))
return;
if (dd.onLockFast(<->dd, m->id, stk))
return;
SpinMutexLock lk(&mtx);
MutexEnsureID(lt, m);
if (wlock) // Only a recursive rlock may be held.
CHECK(!dd.isHeld(<->dd, m->id));
if (!trylock)
dd.addEdges(<->dd, m->id, stk ? stk : cb->Unwind(), cb->UniqueTid());
dd.onLockAfter(<->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
|