1 //===-- tsan_platform_linux.cpp -------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of ThreadSanitizer (TSan), a race detector.
10 //
11 // Linux- and BSD-specific code.
12 //===----------------------------------------------------------------------===//
13
14 #include "sanitizer_common/sanitizer_platform.h"
15 #if SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD
16
17 #include "sanitizer_common/sanitizer_common.h"
18 #include "sanitizer_common/sanitizer_libc.h"
19 #include "sanitizer_common/sanitizer_linux.h"
20 #include "sanitizer_common/sanitizer_platform_limits_netbsd.h"
21 #include "sanitizer_common/sanitizer_platform_limits_posix.h"
22 #include "sanitizer_common/sanitizer_posix.h"
23 #include "sanitizer_common/sanitizer_procmaps.h"
24 #include "sanitizer_common/sanitizer_stackdepot.h"
25 #include "sanitizer_common/sanitizer_stoptheworld.h"
26 #include "tsan_flags.h"
27 #include "tsan_platform.h"
28 #include "tsan_rtl.h"
29
30 #include <fcntl.h>
31 #include <pthread.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <stdarg.h>
37 #include <sys/mman.h>
38 #if SANITIZER_LINUX
39 #include <sys/personality.h>
40 #include <setjmp.h>
41 #endif
42 #include <sys/syscall.h>
43 #include <sys/socket.h>
44 #include <sys/time.h>
45 #include <sys/types.h>
46 #include <sys/resource.h>
47 #include <sys/stat.h>
48 #include <unistd.h>
49 #include <sched.h>
50 #include <dlfcn.h>
51 #if SANITIZER_LINUX
52 #define __need_res_state
53 #include <resolv.h>
54 #endif
55
56 #ifdef sa_handler
57 # undef sa_handler
58 #endif
59
60 #ifdef sa_sigaction
61 # undef sa_sigaction
62 #endif
63
64 #if SANITIZER_FREEBSD
65 extern "C" void *__libc_stack_end;
66 void *__libc_stack_end = 0;
67 #endif
68
69 #if SANITIZER_LINUX && defined(__aarch64__) && !SANITIZER_GO
70 # define INIT_LONGJMP_XOR_KEY 1
71 #else
72 # define INIT_LONGJMP_XOR_KEY 0
73 #endif
74
75 #if INIT_LONGJMP_XOR_KEY
76 #include "interception/interception.h"
77 // Must be declared outside of other namespaces.
78 DECLARE_REAL(int, _setjmp, void *env)
79 #endif
80
81 namespace __tsan {
82
83 #if INIT_LONGJMP_XOR_KEY
84 static void InitializeLongjmpXorKey();
85 static uptr longjmp_xor_key;
86 #endif
87
88 #ifdef TSAN_RUNTIME_VMA
89 // Runtime detected VMA size.
90 uptr vmaSize;
91 #endif
92
93 enum {
94 MemTotal = 0,
95 MemShadow = 1,
96 MemMeta = 2,
97 MemFile = 3,
98 MemMmap = 4,
99 MemTrace = 5,
100 MemHeap = 6,
101 MemOther = 7,
102 MemCount = 8,
103 };
104
FillProfileCallback(uptr p,uptr rss,bool file,uptr * mem,uptr stats_size)105 void FillProfileCallback(uptr p, uptr rss, bool file,
106 uptr *mem, uptr stats_size) {
107 mem[MemTotal] += rss;
108 if (p >= ShadowBeg() && p < ShadowEnd())
109 mem[MemShadow] += rss;
110 else if (p >= MetaShadowBeg() && p < MetaShadowEnd())
111 mem[MemMeta] += rss;
112 #if !SANITIZER_GO
113 else if (p >= HeapMemBeg() && p < HeapMemEnd())
114 mem[MemHeap] += rss;
115 else if (p >= LoAppMemBeg() && p < LoAppMemEnd())
116 mem[file ? MemFile : MemMmap] += rss;
117 else if (p >= HiAppMemBeg() && p < HiAppMemEnd())
118 mem[file ? MemFile : MemMmap] += rss;
119 #else
120 else if (p >= AppMemBeg() && p < AppMemEnd())
121 mem[file ? MemFile : MemMmap] += rss;
122 #endif
123 else if (p >= TraceMemBeg() && p < TraceMemEnd())
124 mem[MemTrace] += rss;
125 else
126 mem[MemOther] += rss;
127 }
128
WriteMemoryProfile(char * buf,uptr buf_size,uptr nthread,uptr nlive)129 void WriteMemoryProfile(char *buf, uptr buf_size, uptr nthread, uptr nlive) {
130 uptr mem[MemCount];
131 internal_memset(mem, 0, sizeof(mem[0]) * MemCount);
132 __sanitizer::GetMemoryProfile(FillProfileCallback, mem, 7);
133 StackDepotStats *stacks = StackDepotGetStats();
134 internal_snprintf(buf, buf_size,
135 "RSS %zd MB: shadow:%zd meta:%zd file:%zd mmap:%zd"
136 " trace:%zd heap:%zd other:%zd stacks=%zd[%zd] nthr=%zd/%zd\n",
137 mem[MemTotal] >> 20, mem[MemShadow] >> 20, mem[MemMeta] >> 20,
138 mem[MemFile] >> 20, mem[MemMmap] >> 20, mem[MemTrace] >> 20,
139 mem[MemHeap] >> 20, mem[MemOther] >> 20,
140 stacks->allocated >> 20, stacks->n_uniq_ids,
141 nlive, nthread);
142 }
143
144 #if SANITIZER_LINUX
FlushShadowMemoryCallback(const SuspendedThreadsList & suspended_threads_list,void * argument)145 void FlushShadowMemoryCallback(
146 const SuspendedThreadsList &suspended_threads_list,
147 void *argument) {
148 ReleaseMemoryPagesToOS(ShadowBeg(), ShadowEnd());
149 }
150 #endif
151
FlushShadowMemory()152 void FlushShadowMemory() {
153 #if SANITIZER_LINUX
154 StopTheWorld(FlushShadowMemoryCallback, 0);
155 #endif
156 }
157
158 #if !SANITIZER_GO
159 // Mark shadow for .rodata sections with the special kShadowRodata marker.
160 // Accesses to .rodata can't race, so this saves time, memory and trace space.
MapRodata()161 static void MapRodata() {
162 // First create temp file.
163 const char *tmpdir = GetEnv("TMPDIR");
164 if (tmpdir == 0)
165 tmpdir = GetEnv("TEST_TMPDIR");
166 #ifdef P_tmpdir
167 if (tmpdir == 0)
168 tmpdir = P_tmpdir;
169 #endif
170 if (tmpdir == 0)
171 return;
172 char name[256];
173 internal_snprintf(name, sizeof(name), "%s/tsan.rodata.%d",
174 tmpdir, (int)internal_getpid());
175 uptr openrv = internal_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
176 if (internal_iserror(openrv))
177 return;
178 internal_unlink(name); // Unlink it now, so that we can reuse the buffer.
179 fd_t fd = openrv;
180 // Fill the file with kShadowRodata.
181 const uptr kMarkerSize = 512 * 1024 / sizeof(u64);
182 InternalMmapVector<u64> marker(kMarkerSize);
183 // volatile to prevent insertion of memset
184 for (volatile u64 *p = marker.data(); p < marker.data() + kMarkerSize; p++)
185 *p = kShadowRodata;
186 internal_write(fd, marker.data(), marker.size() * sizeof(u64));
187 // Map the file into memory.
188 uptr page = internal_mmap(0, GetPageSizeCached(), PROT_READ | PROT_WRITE,
189 MAP_PRIVATE | MAP_ANONYMOUS, fd, 0);
190 if (internal_iserror(page)) {
191 internal_close(fd);
192 return;
193 }
194 // Map the file into shadow of .rodata sections.
195 MemoryMappingLayout proc_maps(/*cache_enabled*/true);
196 // Reusing the buffer 'name'.
197 MemoryMappedSegment segment(name, ARRAY_SIZE(name));
198 while (proc_maps.Next(&segment)) {
199 if (segment.filename[0] != 0 && segment.filename[0] != '[' &&
200 segment.IsReadable() && segment.IsExecutable() &&
201 !segment.IsWritable() && IsAppMem(segment.start)) {
202 // Assume it's .rodata
203 char *shadow_start = (char *)MemToShadow(segment.start);
204 char *shadow_end = (char *)MemToShadow(segment.end);
205 for (char *p = shadow_start; p < shadow_end;
206 p += marker.size() * sizeof(u64)) {
207 internal_mmap(p, Min<uptr>(marker.size() * sizeof(u64), shadow_end - p),
208 PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, 0);
209 }
210 }
211 }
212 internal_close(fd);
213 }
214
InitializeShadowMemoryPlatform()215 void InitializeShadowMemoryPlatform() {
216 MapRodata();
217 }
218
219 #endif // #if !SANITIZER_GO
220
InitializePlatformEarly()221 void InitializePlatformEarly() {
222 #ifdef TSAN_RUNTIME_VMA
223 vmaSize =
224 (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1);
225 #if defined(__aarch64__)
226 # if !SANITIZER_GO
227 if (vmaSize != 39 && vmaSize != 42 && vmaSize != 48) {
228 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
229 Printf("FATAL: Found %zd - Supported 39, 42 and 48\n", vmaSize);
230 Die();
231 }
232 #else
233 if (vmaSize != 48) {
234 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
235 Printf("FATAL: Found %zd - Supported 48\n", vmaSize);
236 Die();
237 }
238 #endif
239 #elif defined(__powerpc64__)
240 # if !SANITIZER_GO
241 if (vmaSize != 44 && vmaSize != 46 && vmaSize != 47) {
242 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
243 Printf("FATAL: Found %zd - Supported 44, 46, and 47\n", vmaSize);
244 Die();
245 }
246 # else
247 if (vmaSize != 46 && vmaSize != 47) {
248 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
249 Printf("FATAL: Found %zd - Supported 46, and 47\n", vmaSize);
250 Die();
251 }
252 # endif
253 #elif defined(__mips64)
254 # if !SANITIZER_GO
255 if (vmaSize != 40) {
256 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
257 Printf("FATAL: Found %zd - Supported 40\n", vmaSize);
258 Die();
259 }
260 # else
261 if (vmaSize != 47) {
262 Printf("FATAL: ThreadSanitizer: unsupported VMA range\n");
263 Printf("FATAL: Found %zd - Supported 47\n", vmaSize);
264 Die();
265 }
266 # endif
267 #endif
268 #endif
269 }
270
InitializePlatform()271 void InitializePlatform() {
272 DisableCoreDumperIfNecessary();
273
274 // Go maps shadow memory lazily and works fine with limited address space.
275 // Unlimited stack is not a problem as well, because the executable
276 // is not compiled with -pie.
277 #if !SANITIZER_GO
278 {
279 bool reexec = false;
280 // TSan doesn't play well with unlimited stack size (as stack
281 // overlaps with shadow memory). If we detect unlimited stack size,
282 // we re-exec the program with limited stack size as a best effort.
283 if (StackSizeIsUnlimited()) {
284 const uptr kMaxStackSize = 32 * 1024 * 1024;
285 VReport(1, "Program is run with unlimited stack size, which wouldn't "
286 "work with ThreadSanitizer.\n"
287 "Re-execing with stack size limited to %zd bytes.\n",
288 kMaxStackSize);
289 SetStackSizeLimitInBytes(kMaxStackSize);
290 reexec = true;
291 }
292
293 if (!AddressSpaceIsUnlimited()) {
294 Report("WARNING: Program is run with limited virtual address space,"
295 " which wouldn't work with ThreadSanitizer.\n");
296 Report("Re-execing with unlimited virtual address space.\n");
297 SetAddressSpaceUnlimited();
298 reexec = true;
299 }
300 #if SANITIZER_LINUX && defined(__aarch64__)
301 // After patch "arm64: mm: support ARCH_MMAP_RND_BITS." is introduced in
302 // linux kernel, the random gap between stack and mapped area is increased
303 // from 128M to 36G on 39-bit aarch64. As it is almost impossible to cover
304 // this big range, we should disable randomized virtual space on aarch64.
305 int old_personality = personality(0xffffffff);
306 if (old_personality != -1 && (old_personality & ADDR_NO_RANDOMIZE) == 0) {
307 VReport(1, "WARNING: Program is run with randomized virtual address "
308 "space, which wouldn't work with ThreadSanitizer.\n"
309 "Re-execing with fixed virtual address space.\n");
310 CHECK_NE(personality(old_personality | ADDR_NO_RANDOMIZE), -1);
311 reexec = true;
312 }
313 // Initialize the xor key used in {sig}{set,long}jump.
314 InitializeLongjmpXorKey();
315 #endif
316 if (reexec)
317 ReExec();
318 }
319
320 CheckAndProtect();
321 InitTlsSize();
322 #endif // !SANITIZER_GO
323 }
324
325 #if !SANITIZER_GO
326 // Extract file descriptors passed to glibc internal __res_iclose function.
327 // This is required to properly "close" the fds, because we do not see internal
328 // closes within glibc. The code is a pure hack.
ExtractResolvFDs(void * state,int * fds,int nfd)329 int ExtractResolvFDs(void *state, int *fds, int nfd) {
330 #if SANITIZER_LINUX && !SANITIZER_ANDROID
331 int cnt = 0;
332 struct __res_state *statp = (struct __res_state*)state;
333 for (int i = 0; i < MAXNS && cnt < nfd; i++) {
334 if (statp->_u._ext.nsaddrs[i] && statp->_u._ext.nssocks[i] != -1)
335 fds[cnt++] = statp->_u._ext.nssocks[i];
336 }
337 return cnt;
338 #else
339 return 0;
340 #endif
341 }
342
343 // Extract file descriptors passed via UNIX domain sockets.
344 // This is requried to properly handle "open" of these fds.
345 // see 'man recvmsg' and 'man 3 cmsg'.
ExtractRecvmsgFDs(void * msgp,int * fds,int nfd)346 int ExtractRecvmsgFDs(void *msgp, int *fds, int nfd) {
347 int res = 0;
348 msghdr *msg = (msghdr*)msgp;
349 struct cmsghdr *cmsg = CMSG_FIRSTHDR(msg);
350 for (; cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
351 if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS)
352 continue;
353 int n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(fds[0]);
354 for (int i = 0; i < n; i++) {
355 fds[res++] = ((int*)CMSG_DATA(cmsg))[i];
356 if (res == nfd)
357 return res;
358 }
359 }
360 return res;
361 }
362
363 // Reverse operation of libc stack pointer mangling
UnmangleLongJmpSp(uptr mangled_sp)364 static uptr UnmangleLongJmpSp(uptr mangled_sp) {
365 #if defined(__x86_64__)
366 # if SANITIZER_LINUX
367 // Reverse of:
368 // xor %fs:0x30, %rsi
369 // rol $0x11, %rsi
370 uptr sp;
371 asm("ror $0x11, %0 \n"
372 "xor %%fs:0x30, %0 \n"
373 : "=r" (sp)
374 : "0" (mangled_sp));
375 return sp;
376 # else
377 return mangled_sp;
378 # endif
379 #elif defined(__aarch64__)
380 # if SANITIZER_LINUX
381 return mangled_sp ^ longjmp_xor_key;
382 # else
383 return mangled_sp;
384 # endif
385 #elif defined(__powerpc64__)
386 // Reverse of:
387 // ld r4, -28696(r13)
388 // xor r4, r3, r4
389 uptr xor_key;
390 asm("ld %0, -28696(%%r13)" : "=r" (xor_key));
391 return mangled_sp ^ xor_key;
392 #elif defined(__mips__)
393 return mangled_sp;
394 #elif defined(__s390x__)
395 // tcbhead_t.stack_guard
396 uptr xor_key = ((uptr *)__builtin_thread_pointer())[5];
397 return mangled_sp ^ xor_key;
398 #else
399 #error "Unknown platform"
400 #endif
401 }
402
403 #if SANITIZER_NETBSD
404 # ifdef __x86_64__
405 # define LONG_JMP_SP_ENV_SLOT 6
406 # else
407 # error unsupported
408 # endif
409 #elif defined(__powerpc__)
410 # define LONG_JMP_SP_ENV_SLOT 0
411 #elif SANITIZER_FREEBSD
412 # define LONG_JMP_SP_ENV_SLOT 2
413 #elif SANITIZER_LINUX
414 # ifdef __aarch64__
415 # define LONG_JMP_SP_ENV_SLOT 13
416 # elif defined(__mips64)
417 # define LONG_JMP_SP_ENV_SLOT 1
418 # elif defined(__s390x__)
419 # define LONG_JMP_SP_ENV_SLOT 9
420 # else
421 # define LONG_JMP_SP_ENV_SLOT 6
422 # endif
423 #endif
424
ExtractLongJmpSp(uptr * env)425 uptr ExtractLongJmpSp(uptr *env) {
426 uptr mangled_sp = env[LONG_JMP_SP_ENV_SLOT];
427 return UnmangleLongJmpSp(mangled_sp);
428 }
429
430 #if INIT_LONGJMP_XOR_KEY
431 // GLIBC mangles the function pointers in jmp_buf (used in {set,long}*jmp
432 // functions) by XORing them with a random key. For AArch64 it is a global
433 // variable rather than a TCB one (as for x86_64/powerpc). We obtain the key by
434 // issuing a setjmp and XORing the SP pointer values to derive the key.
InitializeLongjmpXorKey()435 static void InitializeLongjmpXorKey() {
436 // 1. Call REAL(setjmp), which stores the mangled SP in env.
437 jmp_buf env;
438 REAL(_setjmp)(env);
439
440 // 2. Retrieve vanilla/mangled SP.
441 uptr sp;
442 asm("mov %0, sp" : "=r" (sp));
443 uptr mangled_sp = ((uptr *)&env)[LONG_JMP_SP_ENV_SLOT];
444
445 // 3. xor SPs to obtain key.
446 longjmp_xor_key = mangled_sp ^ sp;
447 }
448 #endif
449
ImitateTlsWrite(ThreadState * thr,uptr tls_addr,uptr tls_size)450 void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
451 // Check that the thr object is in tls;
452 const uptr thr_beg = (uptr)thr;
453 const uptr thr_end = (uptr)thr + sizeof(*thr);
454 CHECK_GE(thr_beg, tls_addr);
455 CHECK_LE(thr_beg, tls_addr + tls_size);
456 CHECK_GE(thr_end, tls_addr);
457 CHECK_LE(thr_end, tls_addr + tls_size);
458 // Since the thr object is huge, skip it.
459 MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr, thr_beg - tls_addr);
460 MemoryRangeImitateWrite(thr, /*pc=*/2, thr_end,
461 tls_addr + tls_size - thr_end);
462 }
463
464 // Note: this function runs with async signals enabled,
465 // so it must not touch any tsan state.
call_pthread_cancel_with_cleanup(int (* fn)(void * arg),void (* cleanup)(void * arg),void * arg)466 int call_pthread_cancel_with_cleanup(int (*fn)(void *arg),
467 void (*cleanup)(void *arg), void *arg) {
468 // pthread_cleanup_push/pop are hardcore macros mess.
469 // We can't intercept nor call them w/o including pthread.h.
470 int res;
471 pthread_cleanup_push(cleanup, arg);
472 res = fn(arg);
473 pthread_cleanup_pop(0);
474 return res;
475 }
476 #endif // !SANITIZER_GO
477
478 #if !SANITIZER_GO
ReplaceSystemMalloc()479 void ReplaceSystemMalloc() { }
480 #endif
481
482 #if !SANITIZER_GO
483 #if SANITIZER_ANDROID
484 // On Android, one thread can call intercepted functions after
485 // DestroyThreadState(), so add a fake thread state for "dead" threads.
486 static ThreadState *dead_thread_state = nullptr;
487
cur_thread()488 ThreadState *cur_thread() {
489 ThreadState* thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
490 if (thr == nullptr) {
491 __sanitizer_sigset_t emptyset;
492 internal_sigfillset(&emptyset);
493 __sanitizer_sigset_t oldset;
494 CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &emptyset, &oldset));
495 thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
496 if (thr == nullptr) {
497 thr = reinterpret_cast<ThreadState*>(MmapOrDie(sizeof(ThreadState),
498 "ThreadState"));
499 *get_android_tls_ptr() = reinterpret_cast<uptr>(thr);
500 if (dead_thread_state == nullptr) {
501 dead_thread_state = reinterpret_cast<ThreadState*>(
502 MmapOrDie(sizeof(ThreadState), "ThreadState"));
503 dead_thread_state->fast_state.SetIgnoreBit();
504 dead_thread_state->ignore_interceptors = 1;
505 dead_thread_state->is_dead = true;
506 *const_cast<u32*>(&dead_thread_state->tid) = -1;
507 CHECK_EQ(0, internal_mprotect(dead_thread_state, sizeof(ThreadState),
508 PROT_READ));
509 }
510 }
511 CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &oldset, nullptr));
512 }
513 return thr;
514 }
515
set_cur_thread(ThreadState * thr)516 void set_cur_thread(ThreadState *thr) {
517 *get_android_tls_ptr() = reinterpret_cast<uptr>(thr);
518 }
519
cur_thread_finalize()520 void cur_thread_finalize() {
521 __sanitizer_sigset_t emptyset;
522 internal_sigfillset(&emptyset);
523 __sanitizer_sigset_t oldset;
524 CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &emptyset, &oldset));
525 ThreadState* thr = reinterpret_cast<ThreadState*>(*get_android_tls_ptr());
526 if (thr != dead_thread_state) {
527 *get_android_tls_ptr() = reinterpret_cast<uptr>(dead_thread_state);
528 UnmapOrDie(thr, sizeof(ThreadState));
529 }
530 CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, &oldset, nullptr));
531 }
532 #endif // SANITIZER_ANDROID
533 #endif // if !SANITIZER_GO
534
535 } // namespace __tsan
536
537 #endif // SANITIZER_LINUX || SANITIZER_FREEBSD || SANITIZER_NETBSD
538