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
|
//===-- asan_stack.cc -------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Code for ASan stack trace.
//===----------------------------------------------------------------------===//
#include "asan_interceptors.h"
#include "asan_lock.h"
#include "asan_procmaps.h"
#include "asan_stack.h"
#include "asan_thread.h"
#include "asan_thread_registry.h"
#ifdef ASAN_USE_EXTERNAL_SYMBOLIZER
extern bool
ASAN_USE_EXTERNAL_SYMBOLIZER(const void *pc, char *out, int out_size);
#endif
namespace __asan {
// ----------------------- AsanStackTrace ----------------------------- {{{1
#if defined(ASAN_USE_EXTERNAL_SYMBOLIZER)
void AsanStackTrace::PrintStack(uintptr_t *addr, size_t size) {
for (size_t i = 0; i < size && addr[i]; i++) {
uintptr_t pc = addr[i];
char buff[4096];
ASAN_USE_EXTERNAL_SYMBOLIZER((void*)pc, buff, sizeof(buff));
Printf(" #%zu 0x%zx %s\n", i, pc, buff);
}
}
#else // ASAN_USE_EXTERNAL_SYMBOLIZER
void AsanStackTrace::PrintStack(uintptr_t *addr, size_t size) {
AsanProcMaps proc_maps;
for (size_t i = 0; i < size && addr[i]; i++) {
proc_maps.Reset();
uintptr_t pc = addr[i];
uintptr_t offset;
char filename[4096];
if (proc_maps.GetObjectNameAndOffset(pc, &offset,
filename, sizeof(filename))) {
Printf(" #%zu 0x%zx (%s+0x%zx)\n", i, pc, filename, offset);
} else {
Printf(" #%zu 0x%zx\n", i, pc);
}
}
}
#endif // ASAN_USE_EXTERNAL_SYMBOLIZER
uintptr_t AsanStackTrace::GetCurrentPc() {
return GET_CALLER_PC();
}
void AsanStackTrace::FastUnwindStack(uintptr_t pc, uintptr_t bp) {
CHECK(size == 0 && trace[0] == pc);
size = 1;
if (!asan_inited) return;
AsanThread *t = asanThreadRegistry().GetCurrent();
if (!t) return;
uintptr_t *frame = (uintptr_t*)bp;
uintptr_t *prev_frame = frame;
uintptr_t *top = (uintptr_t*)t->stack_top();
uintptr_t *bottom = (uintptr_t*)t->stack_bottom();
while (frame >= prev_frame &&
frame < top - 2 &&
frame > bottom &&
size < max_size) {
uintptr_t pc1 = frame[1];
if (pc1 != pc) {
trace[size++] = pc1;
}
prev_frame = frame;
frame = (uintptr_t*)frame[0];
}
}
// On 32-bits we don't compress stack traces.
// On 64-bits we compress stack traces: if a given pc differes slightly from
// the previous one, we record a 31-bit offset instead of the full pc.
size_t AsanStackTrace::CompressStack(AsanStackTrace *stack,
uint32_t *compressed, size_t size) {
#if __WORDSIZE == 32
// Don't compress, just copy.
size_t res = 0;
for (size_t i = 0; i < stack->size && i < size; i++) {
compressed[i] = stack->trace[i];
res++;
}
if (stack->size < size)
compressed[stack->size] = 0;
#else // 64 bits, compress.
uintptr_t prev_pc = 0;
const uintptr_t kMaxOffset = (1ULL << 30) - 1;
uintptr_t c_index = 0;
size_t res = 0;
for (size_t i = 0, n = stack->size; i < n; i++) {
uintptr_t pc = stack->trace[i];
if (!pc) break;
if ((int64_t)pc < 0) break;
// Printf("C pc[%zu] %zx\n", i, pc);
if (prev_pc - pc < kMaxOffset || pc - prev_pc < kMaxOffset) {
uintptr_t offset = (int64_t)(pc - prev_pc);
offset |= (1U << 31);
if (c_index >= size) break;
// Printf("C co[%zu] offset %zx\n", i, offset);
compressed[c_index++] = offset;
} else {
uintptr_t hi = pc >> 32;
uintptr_t lo = (pc << 32) >> 32;
CHECK((hi & (1 << 31)) == 0);
if (c_index + 1 >= size) break;
// Printf("C co[%zu] hi/lo: %zx %zx\n", c_index, hi, lo);
compressed[c_index++] = hi;
compressed[c_index++] = lo;
}
res++;
prev_pc = pc;
}
if (c_index < size)
compressed[c_index] = 0;
if (c_index + 1 < size)
compressed[c_index + 1] = 0;
#endif // __WORDSIZE
// debug-only code
#if 0
AsanStackTrace check_stack;
UncompressStack(&check_stack, compressed, size);
if (res < check_stack.size) {
Printf("res %zu check_stack.size %zu; c_size %zu\n", res,
check_stack.size, size);
}
// |res| may be greater than check_stack.size, because
// UncompressStack(CompressStack(stack)) eliminates the 0x0 frames.
CHECK(res >= check_stack.size);
CHECK(0 == REAL(memcmp)(check_stack.trace, stack->trace,
check_stack.size * sizeof(uintptr_t)));
#endif
return res;
}
void AsanStackTrace::UncompressStack(AsanStackTrace *stack,
uint32_t *compressed, size_t size) {
#if __WORDSIZE == 32
// Don't uncompress, just copy.
stack->size = 0;
for (size_t i = 0; i < size && i < kStackTraceMax; i++) {
if (!compressed[i]) break;
stack->size++;
stack->trace[i] = compressed[i];
}
#else // 64 bits, uncompress
uintptr_t prev_pc = 0;
stack->size = 0;
for (size_t i = 0; i < size && stack->size < kStackTraceMax; i++) {
uint32_t x = compressed[i];
uintptr_t pc = 0;
if (x & (1U << 31)) {
// Printf("U co[%zu] offset: %x\n", i, x);
// this is an offset
int32_t offset = x;
offset = (offset << 1) >> 1; // remove the 31-byte and sign-extend.
pc = prev_pc + offset;
CHECK(pc);
} else {
// CHECK(i + 1 < size);
if (i + 1 >= size) break;
uintptr_t hi = x;
uintptr_t lo = compressed[i+1];
// Printf("U co[%zu] hi/lo: %zx %zx\n", i, hi, lo);
i++;
pc = (hi << 32) | lo;
if (!pc) break;
}
// Printf("U pc[%zu] %zx\n", stack->size, pc);
stack->trace[stack->size++] = pc;
prev_pc = pc;
}
#endif // __WORDSIZE
}
} // namespace __asan
|
