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tsan: improve detection of stack/tls races 

Print meaningful stack frames for stack/tls races
(instead of PC 1/2 that don't symbolize).

Imitate stack/tls writes after we create and initialize
the new thread, otherwise the races are not detected.

This is re-submit of the following reverted commits,
but without tests as they failed on a number of OSes/arches:
"tsan: fix and test detection of TLS races"
"tsan: fix tls_race3 test on darwin"
"tsan: print a meaningful frame for stack races"

Differential Revision: https://reviews.llvm.org/D111147
This commit is contained in:
Dmitry Vyukov 2021-10-05 15:26:02 +02:00
parent 070b0af9b8
commit c483140f3c
3 changed files with 31 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp
View File

@ -453,6 +453,8 @@ static void InitializeLongjmpXorKey() {
}
#endif
extern "C" void __tsan_tls_initialization() {}
void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
// Check that the thr object is in tls;
const uptr thr_beg = (uptr)thr;
@ -462,9 +464,10 @@ void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
CHECK_GE(thr_end, tls_addr);
CHECK_LE(thr_end, tls_addr + tls_size);
// Since the thr object is huge, skip it.
MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr, thr_beg - tls_addr);
MemoryRangeImitateWrite(thr, /*pc=*/2, thr_end,
tls_addr + tls_size - thr_end);
const uptr pc = StackTrace::GetNextInstructionPc(
reinterpret_cast<uptr>(__tsan_tls_initialization));
MemoryRangeImitateWrite(thr, pc, tls_addr, thr_beg - tls_addr);
MemoryRangeImitateWrite(thr, pc, thr_end, tls_addr + tls_size - thr_end);
}
// Note: this function runs with async signals enabled,

12
compiler-rt/lib/tsan/rtl/tsan_platform_mac.cpp
View File

@ -283,13 +283,17 @@ uptr ExtractLongJmpSp(uptr *env) {
}
#if !SANITIZER_GO
extern "C" void __tsan_tls_initialization() {}
void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
// The pointer to the ThreadState object is stored in the shadow memory
// of the tls.
uptr tls_end = tls_addr + tls_size;
uptr thread_identity = (uptr)pthread_self();
const uptr pc = StackTrace::GetNextInstructionPc(
reinterpret_cast<uptr>(__tsan_tls_initialization));
if (thread_identity == main_thread_identity) {
MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr, tls_size);
MemoryRangeImitateWrite(thr, pc, tls_addr, tls_size);
} else {
uptr thr_state_start = thread_identity;
uptr thr_state_end = thr_state_start + sizeof(uptr);
@ -297,10 +301,8 @@ void ImitateTlsWrite(ThreadState *thr, uptr tls_addr, uptr tls_size) {
CHECK_LE(thr_state_start, tls_addr + tls_size);
CHECK_GE(thr_state_end, tls_addr);
CHECK_LE(thr_state_end, tls_addr + tls_size);
MemoryRangeImitateWrite(thr, /*pc=*/2, tls_addr,
thr_state_start - tls_addr);
MemoryRangeImitateWrite(thr, /*pc=*/2, thr_state_end,
tls_end - thr_state_end);
MemoryRangeImitateWrite(thr, pc, tls_addr, thr_state_start - tls_addr);
MemoryRangeImitateWrite(thr, pc, thr_state_end, tls_end - thr_state_end);
}
}
#endif

25
compiler-rt/lib/tsan/rtl/tsan_rtl_thread.cpp
View File

@ -138,6 +138,8 @@ void ThreadContext::OnCreated(void *arg) {
creation_stack_id = CurrentStackId(args->thr, args->pc);
}
extern "C" void __tsan_stack_initialization() {}
struct OnStartedArgs {
ThreadState *thr;
uptr stk_addr;
@ -156,13 +158,6 @@ void ThreadStart(ThreadState *thr, Tid tid, tid_t os_id,
if (thread_type != ThreadType::Fiber)
GetThreadStackAndTls(tid == kMainTid, &stk_addr, &stk_size, &tls_addr,
&tls_size);
if (tid != kMainTid) {
if (stk_addr && stk_size)
MemoryRangeImitateWrite(thr, /*pc=*/ 1, stk_addr, stk_size);
if (tls_addr && tls_size) ImitateTlsWrite(thr, tls_addr, tls_size);
}
#endif
ThreadRegistry *tr = &ctx->thread_registry;
@ -178,6 +173,22 @@ void ThreadStart(ThreadState *thr, Tid tid, tid_t os_id,
ThreadIgnoreSyncBegin(thr, 0);
}
#endif
#if !SANITIZER_GO
// Don't imitate stack/TLS writes for the main thread,
// because its initialization is synchronized with all
// subsequent threads anyway.
if (tid != kMainTid) {
if (stk_addr && stk_size) {
const uptr pc = StackTrace::GetNextInstructionPc(
reinterpret_cast<uptr>(__tsan_stack_initialization));
MemoryRangeImitateWrite(thr, pc, stk_addr, stk_size);
}
if (tls_addr && tls_size)
ImitateTlsWrite(thr, tls_addr, tls_size);
}
#endif
}
void ThreadContext::OnStarted(void *arg) {