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//===-- tsan_rtl_report.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
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer (TSan), a race detector.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_placement_new.h"
#include "sanitizer_common/sanitizer_stackdepot.h"
#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_stacktrace.h"
#include "tsan_platform.h"
#include "tsan_rtl.h"
#include "tsan_suppressions.h"
#include "tsan_symbolize.h"
#include "tsan_report.h"
#include "tsan_sync.h"
#include "tsan_mman.h"
#include "tsan_flags.h"
#include "tsan_fd.h"
namespace __tsan {
using namespace __sanitizer;
static ReportStack *SymbolizeStack(StackTrace trace);
// Can be overriden by an application/test to intercept reports.
#ifdef TSAN_EXTERNAL_HOOKS
bool OnReport(const ReportDesc *rep, bool suppressed);
#else
SANITIZER_WEAK_CXX_DEFAULT_IMPL
bool OnReport(const ReportDesc *rep, bool suppressed) {
(void)rep;
return suppressed;
}
#endif
SANITIZER_WEAK_DEFAULT_IMPL
void __tsan_on_report(const ReportDesc *rep) {
(void)rep;
}
static void StackStripMain(SymbolizedStack *frames) {
SymbolizedStack *last_frame = nullptr;
SymbolizedStack *last_frame2 = nullptr;
for (SymbolizedStack *cur = frames; cur; cur = cur->next) {
last_frame2 = last_frame;
last_frame = cur;
}
if (last_frame2 == 0)
return;
#if !SANITIZER_GO
const char *last = last_frame->info.function;
const char *last2 = last_frame2->info.function;
// Strip frame above 'main'
if (last2 && 0 == internal_strcmp(last2, "main")) {
last_frame->ClearAll();
last_frame2->next = nullptr;
// Strip our internal thread start routine.
} else if (last && 0 == internal_strcmp(last, "__tsan_thread_start_func")) {
last_frame->ClearAll();
last_frame2->next = nullptr;
// Strip global ctors init, .preinit_array and main caller.
} else if (last && (0 == internal_strcmp(last, "__do_global_ctors_aux") ||
0 == internal_strcmp(last, "__libc_csu_init") ||
0 == internal_strcmp(last, "__libc_start_main"))) {
last_frame->ClearAll();
last_frame2->next = nullptr;
// If both are 0, then we probably just failed to symbolize.
} else if (last || last2) {
// Ensure that we recovered stack completely. Trimmed stack
// can actually happen if we do not instrument some code,
// so it's only a debug print. However we must try hard to not miss it
// due to our fault.
DPrintf("Bottom stack frame is missed\n");
}
#else
// The last frame always point into runtime (gosched0, goexit0, runtime.main).
last_frame->ClearAll();
last_frame2->next = nullptr;
#endif
}
ReportStack *SymbolizeStackId(u32 stack_id) {
if (stack_id == 0)
return 0;
StackTrace stack = StackDepotGet(stack_id);
if (stack.trace == nullptr)
return nullptr;
return SymbolizeStack(stack);
}
static ReportStack *SymbolizeStack(StackTrace trace) {
if (trace.size == 0)
return 0;
SymbolizedStack *top = nullptr;
for (uptr si = 0; si < trace.size; si++) {
const uptr pc = trace.trace[si];
uptr pc1 = pc;
// We obtain the return address, but we're interested in the previous
// instruction.
if ((pc & kExternalPCBit) == 0)
pc1 = StackTrace::GetPreviousInstructionPc(pc);
SymbolizedStack *ent = SymbolizeCode(pc1);
CHECK_NE(ent, 0);
SymbolizedStack *last = ent;
while (last->next) {
last->info.address = pc; // restore original pc for report
last = last->next;
}
last->info.address = pc; // restore original pc for report
last->next = top;
top = ent;
}
StackStripMain(top);
auto *stack = New<ReportStack>();
stack->frames = top;
return stack;
}
bool ShouldReport(ThreadState *thr, ReportType typ) {
// We set thr->suppress_reports in the fork context.
// Taking any locking in the fork context can lead to deadlocks.
// If any locks are already taken, it's too late to do this check.
CheckedMutex::CheckNoLocks();
// For the same reason check we didn't lock thread_registry yet.
if (SANITIZER_DEBUG)
ThreadRegistryLock l(&ctx->thread_registry);
if (!flags()->report_bugs || thr->suppress_reports)
return false;
switch (typ) {
case ReportTypeSignalUnsafe:
return flags()->report_signal_unsafe;
case ReportTypeThreadLeak:
#if !SANITIZER_GO
// It's impossible to join phantom threads
// in the child after fork.
if (ctx->after_multithreaded_fork)
return false;
#endif
return flags()->report_thread_leaks;
case ReportTypeMutexDestroyLocked:
return flags()->report_destroy_locked;
default:
return true;
}
}
ScopedReportBase::ScopedReportBase(ReportType typ, uptr tag) {
ctx->thread_registry.CheckLocked();
rep_ = New<ReportDesc>();
rep_->typ = typ;
rep_->tag = tag;
ctx->report_mtx.Lock();
}
ScopedReportBase::~ScopedReportBase() {
ctx->report_mtx.Unlock();
DestroyAndFree(rep_);
}
void ScopedReportBase::AddStack(StackTrace stack, bool suppressable) {
ReportStack **rs = rep_->stacks.PushBack();
*rs = SymbolizeStack(stack);
(*rs)->suppressable = suppressable;
}
void ScopedReportBase::AddMemoryAccess(uptr addr, uptr external_tag, Shadow s,
StackTrace stack, const MutexSet *mset) {
auto *mop = New<ReportMop>();
rep_->mops.PushBack(mop);
mop->tid = s.tid();
mop->addr = addr + s.addr0();
mop->size = s.size();
mop->write = s.IsWrite();
mop->atomic = s.IsAtomic();
mop->stack = SymbolizeStack(stack);
mop->external_tag = external_tag;
if (mop->stack)
mop->stack->suppressable = true;
for (uptr i = 0; i < mset->Size(); i++) {
MutexSet::Desc d = mset->Get(i);
u64 mid = this->AddMutex(d.id);
ReportMopMutex mtx = {mid, d.write};
mop->mset.PushBack(mtx);
}
}
void ScopedReportBase::AddUniqueTid(Tid unique_tid) {
rep_->unique_tids.PushBack(unique_tid);
}
void ScopedReportBase::AddThread(const ThreadContext *tctx, bool suppressable) {
for (uptr i = 0; i < rep_->threads.Size(); i++) {
if ((u32)rep_->threads[i]->id == tctx->tid)
return;
}
auto *rt = New<ReportThread>();
rep_->threads.PushBack(rt);
rt->id = tctx->tid;
rt->os_id = tctx->os_id;
rt->running = (tctx->status == ThreadStatusRunning);
rt->name = internal_strdup(tctx->name);
rt->parent_tid = tctx->parent_tid;
rt->thread_type = tctx->thread_type;
rt->stack = 0;
rt->stack = SymbolizeStackId(tctx->creation_stack_id);
if (rt->stack)
rt->stack->suppressable = suppressable;
}
#if !SANITIZER_GO
static bool FindThreadByUidLockedCallback(ThreadContextBase *tctx, void *arg) {
int unique_id = *(int *)arg;
return tctx->unique_id == (u32)unique_id;
}
static ThreadContext *FindThreadByUidLocked(Tid unique_id) {
ctx->thread_registry.CheckLocked();
return static_cast<ThreadContext *>(
ctx->thread_registry.FindThreadContextLocked(
FindThreadByUidLockedCallback, &unique_id));
}
static ThreadContext *FindThreadByTidLocked(Tid tid) {
ctx->thread_registry.CheckLocked();
return static_cast<ThreadContext *>(
ctx->thread_registry.GetThreadLocked(tid));
}
static bool IsInStackOrTls(ThreadContextBase *tctx_base, void *arg) {
uptr addr = (uptr)arg;
ThreadContext *tctx = static_cast<ThreadContext*>(tctx_base);
if (tctx->status != ThreadStatusRunning)
return false;
ThreadState *thr = tctx->thr;
CHECK(thr);
return ((addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size) ||
(addr >= thr->tls_addr && addr < thr->tls_addr + thr->tls_size));
}
ThreadContext *IsThreadStackOrTls(uptr addr, bool *is_stack) {
ctx->thread_registry.CheckLocked();
ThreadContext *tctx =
static_cast<ThreadContext *>(ctx->thread_registry.FindThreadContextLocked(
IsInStackOrTls, (void *)addr));
if (!tctx)
return 0;
ThreadState *thr = tctx->thr;
CHECK(thr);
*is_stack = (addr >= thr->stk_addr && addr < thr->stk_addr + thr->stk_size);
return tctx;
}
#endif
void ScopedReportBase::AddThread(Tid unique_tid, bool suppressable) {
#if !SANITIZER_GO
if (const ThreadContext *tctx = FindThreadByUidLocked(unique_tid))
AddThread(tctx, suppressable);
#endif
}
void ScopedReportBase::AddMutex(const SyncVar *s) {
for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
if (rep_->mutexes[i]->id == s->uid)
return;
}
auto *rm = New<ReportMutex>();
rep_->mutexes.PushBack(rm);
rm->id = s->uid;
rm->addr = s->addr;
rm->destroyed = false;
rm->stack = SymbolizeStackId(s->creation_stack_id);
}
u64 ScopedReportBase::AddMutex(u64 id) {
u64 uid = 0;
u64 mid = id;
uptr addr = SyncVar::SplitId(id, &uid);
SyncVar *s = ctx->metamap.GetSyncIfExists(addr);
// Check that the mutex is still alive.
// Another mutex can be created at the same address,
// so check uid as well.
if (s && s->CheckId(uid)) {
Lock l(&s->mtx);
mid = s->uid;
AddMutex(s);
} else {
AddDeadMutex(id);
}
return mid;
}
void ScopedReportBase::AddDeadMutex(u64 id) {
for (uptr i = 0; i < rep_->mutexes.Size(); i++) {
if (rep_->mutexes[i]->id == id)
return;
}
auto *rm = New<ReportMutex>();
rep_->mutexes.PushBack(rm);
rm->id = id;
rm->addr = 0;
rm->destroyed = true;
rm->stack = 0;
}
void ScopedReportBase::AddLocation(uptr addr, uptr size) {
if (addr == 0)
return;
#if !SANITIZER_GO
int fd = -1;
Tid creat_tid = kInvalidTid;
StackID creat_stack = 0;
if (FdLocation(addr, &fd, &creat_tid, &creat_stack)) {
auto *loc = New<ReportLocation>();
loc->type = ReportLocationFD;
loc->fd = fd;
loc->tid = creat_tid;
loc->stack = SymbolizeStackId(creat_stack);
rep_->locs.PushBack(loc);
ThreadContext *tctx = FindThreadByUidLocked(creat_tid);
if (tctx)
AddThread(tctx);
return;
}
MBlock *b = 0;
uptr block_begin = 0;
Allocator *a = allocator();
if (a->PointerIsMine((void*)addr)) {
block_begin = (uptr)a->GetBlockBegin((void *)addr);
if (block_begin)
b = ctx->metamap.GetBlock(block_begin);
}
if (!b)
b = JavaHeapBlock(addr, &block_begin);
if (b != 0) {
ThreadContext *tctx = FindThreadByTidLocked(b->tid);
auto *loc = New<ReportLocation>();
loc->type = ReportLocationHeap;
loc->heap_chunk_start = (uptr)allocator()->GetBlockBegin((void *)addr);
loc->heap_chunk_size = b->siz;
loc->external_tag = b->tag;
loc->tid = tctx ? tctx->tid : b->tid;
loc->stack = SymbolizeStackId(b->stk);
rep_->locs.PushBack(loc);
if (tctx)
AddThread(tctx);
return;
}
bool is_stack = false;
if (ThreadContext *tctx = IsThreadStackOrTls(addr, &is_stack)) {
auto *loc = New<ReportLocation>();
loc->type = is_stack ? ReportLocationStack : ReportLocationTLS;
loc->tid = tctx->tid;
rep_->locs.PushBack(loc);
AddThread(tctx);
}
#endif
if (ReportLocation *loc = SymbolizeData(addr)) {
loc->suppressable = true;
rep_->locs.PushBack(loc);
return;
}
}
#if !SANITIZER_GO
void ScopedReportBase::AddSleep(StackID stack_id) {
rep_->sleep = SymbolizeStackId(stack_id);
}
#endif
void ScopedReportBase::SetCount(int count) { rep_->count = count; }
const ReportDesc *ScopedReportBase::GetReport() const { return rep_; }
ScopedReport::ScopedReport(ReportType typ, uptr tag)
: ScopedReportBase(typ, tag) {}
ScopedReport::~ScopedReport() {}
void RestoreStack(Tid tid, const u64 epoch, VarSizeStackTrace *stk,
MutexSet *mset, uptr *tag) {
// This function restores stack trace and mutex set for the thread/epoch.
// It does so by getting stack trace and mutex set at the beginning of
// trace part, and then replaying the trace till the given epoch.
Trace* trace = ThreadTrace(tid);
ReadLock l(&trace->mtx);
const int partidx = (epoch / kTracePartSize) % TraceParts();
TraceHeader* hdr = &trace->headers[partidx];
if (epoch < hdr->epoch0 || epoch >= hdr->epoch0 + kTracePartSize)
return;
CHECK_EQ(RoundDown(epoch, kTracePartSize), hdr->epoch0);
const u64 epoch0 = RoundDown(epoch, TraceSize());
const u64 eend = epoch % TraceSize();
const u64 ebegin = RoundDown(eend, kTracePartSize);
DPrintf("#%d: RestoreStack epoch=%zu ebegin=%zu eend=%zu partidx=%d\n",
tid, (uptr)epoch, (uptr)ebegin, (uptr)eend, partidx);
Vector<uptr> stack;
stack.Resize(hdr->stack0.size + 64);
for (uptr i = 0; i < hdr->stack0.size; i++) {
stack[i] = hdr->stack0.trace[i];
DPrintf2(" #%02zu: pc=%zx\n", i, stack[i]);
}
if (mset)
*mset = hdr->mset0;
uptr pos = hdr->stack0.size;
Event *events = (Event*)GetThreadTrace(tid);
for (uptr i = ebegin; i <= eend; i++) {
Event ev = events[i];
EventType typ = (EventType)(ev >> kEventPCBits);
uptr pc = (uptr)(ev & ((1ull << kEventPCBits) - 1));
DPrintf2(" %zu typ=%d pc=%zx\n", i, typ, pc);
if (typ == EventTypeMop) {
stack[pos] = pc;
} else if (typ == EventTypeFuncEnter) {
if (stack.Size() < pos + 2)
stack.Resize(pos + 2);
stack[pos++] = pc;
} else if (typ == EventTypeFuncExit) {
if (pos > 0)
pos--;
}
if (mset) {
if (typ == EventTypeLock) {
mset->Add(pc, true, epoch0 + i);
} else if (typ == EventTypeUnlock) {
mset->Del(pc, true);
} else if (typ == EventTypeRLock) {
mset->Add(pc, false, epoch0 + i);
} else if (typ == EventTypeRUnlock) {
mset->Del(pc, false);
}
}
for (uptr j = 0; j <= pos; j++)
DPrintf2(" #%zu: %zx\n", j, stack[j]);
}
if (pos == 0 && stack[0] == 0)
return;
pos++;
stk->Init(&stack[0], pos);
ExtractTagFromStack(stk, tag);
}
namespace v3 {
// Replays the trace up to last_pos position in the last part
// or up to the provided epoch/sid (whichever is earlier)
// and calls the provided function f for each event.
template <typename Func>
void TraceReplay(Trace *trace, TracePart *last, Event *last_pos, Sid sid,
Epoch epoch, Func f) {
TracePart *part = trace->parts.Front();
Sid ev_sid = kFreeSid;
Epoch ev_epoch = kEpochOver;
for (;;) {
DCHECK_EQ(part->trace, trace);
// Note: an event can't start in the last element.
// Since an event can take up to 2 elements,
// we ensure we have at least 2 before adding an event.
Event *end = &part->events[TracePart::kSize - 1];
if (part == last)
end = last_pos;
for (Event *evp = &part->events[0]; evp < end; evp++) {
Event *evp0 = evp;
if (!evp->is_access && !evp->is_func) {
switch (evp->type) {
case EventType::kTime: {
auto *ev = reinterpret_cast<EventTime *>(evp);
ev_sid = static_cast<Sid>(ev->sid);
ev_epoch = static_cast<Epoch>(ev->epoch);
if (ev_sid == sid && ev_epoch > epoch)
return;
break;
}
case EventType::kAccessExt:
FALLTHROUGH;
case EventType::kAccessRange:
FALLTHROUGH;
case EventType::kLock:
FALLTHROUGH;
case EventType::kRLock:
// These take 2 Event elements.
evp++;
break;
case EventType::kUnlock:
// This takes 1 Event element.
break;
}
}
CHECK_NE(ev_sid, kFreeSid);
CHECK_NE(ev_epoch, kEpochOver);
f(ev_sid, ev_epoch, evp0);
}
if (part == last)
return;
part = trace->parts.Next(part);
CHECK(part);
}
CHECK(0);
}
static void RestoreStackMatch(VarSizeStackTrace *pstk, MutexSet *pmset,
Vector<uptr> *stack, MutexSet *mset, uptr pc,
bool *found) {
DPrintf2(" MATCHED\n");
*pmset = *mset;
stack->PushBack(pc);
pstk->Init(&(*stack)[0], stack->Size());
stack->PopBack();
*found = true;
}
// Checks if addr1|size1 is fully contained in addr2|size2.
// We check for fully contained instread of just overlapping
// because a memory access is always traced once, but can be
// split into multiple accesses in the shadow.
static constexpr bool IsWithinAccess(uptr addr1, uptr size1, uptr addr2,
uptr size2) {
return addr1 >= addr2 && addr1 + size1 <= addr2 + size2;
}
// Replays the trace of thread tid up to the target event identified
// by sid/epoch/addr/size/typ and restores and returns stack, mutex set
// and tag for that event. If there are multiple such events, it returns
// the last one. Returns false if the event is not present in the trace.
bool RestoreStack(Tid tid, EventType type, Sid sid, Epoch epoch, uptr addr,
uptr size, AccessType typ, VarSizeStackTrace *pstk,
MutexSet *pmset, uptr *ptag) {
// This function restores stack trace and mutex set for the thread/epoch.
// It does so by getting stack trace and mutex set at the beginning of
// trace part, and then replaying the trace till the given epoch.
DPrintf2("RestoreStack: tid=%u sid=%u@%u addr=0x%zx/%zu typ=%x\n", tid,
static_cast<int>(sid), static_cast<int>(epoch), addr, size,
static_cast<int>(typ));
ctx->slot_mtx.CheckLocked(); // needed to prevent trace part recycling
ctx->thread_registry.CheckLocked();
ThreadContext *tctx =
static_cast<ThreadContext *>(ctx->thread_registry.GetThreadLocked(tid));
Trace *trace = &tctx->trace;
// Snapshot first/last parts and the current position in the last part.
TracePart *first_part;
TracePart *last_part;
Event *last_pos;
{
Lock lock(&trace->mtx);
first_part = trace->parts.Front();
if (!first_part)
return false;
last_part = trace->parts.Back();
last_pos = trace->final_pos;
if (tctx->thr)
last_pos = (Event *)atomic_load_relaxed(&tctx->thr->trace_pos);
}
DynamicMutexSet mset;
Vector<uptr> stack;
uptr prev_pc = 0;
bool found = false;
bool is_read = typ & kAccessRead;
bool is_atomic = typ & kAccessAtomic;
bool is_free = typ & kAccessFree;
TraceReplay(
trace, last_part, last_pos, sid, epoch,
[&](Sid ev_sid, Epoch ev_epoch, Event *evp) {
bool match = ev_sid == sid && ev_epoch == epoch;
if (evp->is_access) {
if (evp->is_func == 0 && evp->type == EventType::kAccessExt &&
evp->_ == 0) // NopEvent
return;
auto *ev = reinterpret_cast<EventAccess *>(evp);
uptr ev_addr = RestoreAddr(ev->addr);
uptr ev_size = 1 << ev->size_log;
uptr ev_pc =
prev_pc + ev->pc_delta - (1 << (EventAccess::kPCBits - 1));
prev_pc = ev_pc;
DPrintf2(" Access: pc=0x%zx addr=0x%zx/%zu type=%u/%u\n", ev_pc,
ev_addr, ev_size, ev->is_read, ev->is_atomic);
if (match && type == EventType::kAccessExt &&
IsWithinAccess(addr, size, ev_addr, ev_size) &&
is_read == ev->is_read && is_atomic == ev->is_atomic && !is_free)
RestoreStackMatch(pstk, pmset, &stack, mset, ev_pc, &found);
return;
}
if (evp->is_func) {
auto *ev = reinterpret_cast<EventFunc *>(evp);
if (ev->pc) {
DPrintf2(" FuncEnter: pc=0x%llx\n", ev->pc);
stack.PushBack(ev->pc);
} else {
DPrintf2(" FuncExit\n");
CHECK(stack.Size());
stack.PopBack();
}
return;
}
switch (evp->type) {
case EventType::kAccessExt: {
auto *ev = reinterpret_cast<EventAccessExt *>(evp);
uptr ev_addr = RestoreAddr(ev->addr);
uptr ev_size = 1 << ev->size_log;
prev_pc = ev->pc;
DPrintf2(" AccessExt: pc=0x%llx addr=0x%zx/%zu type=%u/%u\n",
ev->pc, ev_addr, ev_size, ev->is_read, ev->is_atomic);
if (match && type == EventType::kAccessExt &&
IsWithinAccess(addr, size, ev_addr, ev_size) &&
is_read == ev->is_read && is_atomic == ev->is_atomic &&
!is_free)
RestoreStackMatch(pstk, pmset, &stack, mset, ev->pc, &found);
break;
}
case EventType::kAccessRange: {
auto *ev = reinterpret_cast<EventAccessRange *>(evp);
uptr ev_addr = RestoreAddr(ev->addr);
uptr ev_size =
(ev->size_hi << EventAccessRange::kSizeLoBits) + ev->size_lo;
uptr ev_pc = RestoreAddr(ev->pc);
prev_pc = ev_pc;
DPrintf2(" Range: pc=0x%zx addr=0x%zx/%zu type=%u/%u\n", ev_pc,
ev_addr, ev_size, ev->is_read, ev->is_free);
if (match && type == EventType::kAccessExt &&
IsWithinAccess(addr, size, ev_addr, ev_size) &&
is_read == ev->is_read && !is_atomic && is_free == ev->is_free)
RestoreStackMatch(pstk, pmset, &stack, mset, ev_pc, &found);
break;
}
case EventType::kLock:
FALLTHROUGH;
case EventType::kRLock: {
auto *ev = reinterpret_cast<EventLock *>(evp);
bool is_write = ev->type == EventType::kLock;
uptr ev_addr = RestoreAddr(ev->addr);
uptr ev_pc = RestoreAddr(ev->pc);
StackID stack_id =
(ev->stack_hi << EventLock::kStackIDLoBits) + ev->stack_lo;
DPrintf2(" Lock: pc=0x%zx addr=0x%zx stack=%u write=%d\n", ev_pc,
ev_addr, stack_id, is_write);
mset->AddAddr(ev_addr, stack_id, is_write);
// Events with ev_pc == 0 are written to the beginning of trace
// part as initial mutex set (are not real).
if (match && type == EventType::kLock && addr == ev_addr && ev_pc)
RestoreStackMatch(pstk, pmset, &stack, mset, ev_pc, &found);
break;
}
case EventType::kUnlock: {
auto *ev = reinterpret_cast<EventUnlock *>(evp);
uptr ev_addr = RestoreAddr(ev->addr);
DPrintf2(" Unlock: addr=0x%zx\n", ev_addr);
mset->DelAddr(ev_addr);
break;
}
case EventType::kTime:
// TraceReplay already extracted sid/epoch from it,
// nothing else to do here.
break;
}
});
ExtractTagFromStack(pstk, ptag);
return found;
}
} // namespace v3
bool RacyStacks::operator==(const RacyStacks &other) const {
if (hash[0] == other.hash[0] && hash[1] == other.hash[1])
return true;
if (hash[0] == other.hash[1] && hash[1] == other.hash[0])
return true;
return false;
}
static bool FindRacyStacks(const RacyStacks &hash) {
for (uptr i = 0; i < ctx->racy_stacks.Size(); i++) {
if (hash == ctx->racy_stacks[i]) {
VPrintf(2, "ThreadSanitizer: suppressing report as doubled (stack)\n");
return true;
}
}
return false;
}
static bool HandleRacyStacks(ThreadState *thr, VarSizeStackTrace traces[2]) {
if (!flags()->suppress_equal_stacks)
return false;
RacyStacks hash;
hash.hash[0] = md5_hash(traces[0].trace, traces[0].size * sizeof(uptr));
hash.hash[1] = md5_hash(traces[1].trace, traces[1].size * sizeof(uptr));
{
ReadLock lock(&ctx->racy_mtx);
if (FindRacyStacks(hash))
return true;
}
Lock lock(&ctx->racy_mtx);
if (FindRacyStacks(hash))
return true;
ctx->racy_stacks.PushBack(hash);
return false;
}
static bool FindRacyAddress(const RacyAddress &ra0) {
for (uptr i = 0; i < ctx->racy_addresses.Size(); i++) {
RacyAddress ra2 = ctx->racy_addresses[i];
uptr maxbeg = max(ra0.addr_min, ra2.addr_min);
uptr minend = min(ra0.addr_max, ra2.addr_max);
if (maxbeg < minend) {
VPrintf(2, "ThreadSanitizer: suppressing report as doubled (addr)\n");
return true;
}
}
return false;
}
static bool HandleRacyAddress(ThreadState *thr, uptr addr_min, uptr addr_max) {
if (!flags()->suppress_equal_addresses)
return false;
RacyAddress ra0 = {addr_min, addr_max};
{
ReadLock lock(&ctx->racy_mtx);
if (FindRacyAddress(ra0))
return true;
}
Lock lock(&ctx->racy_mtx);
if (FindRacyAddress(ra0))
return true;
ctx->racy_addresses.PushBack(ra0);
return false;
}
bool OutputReport(ThreadState *thr, const ScopedReport &srep) {
// These should have been checked in ShouldReport.
// It's too late to check them here, we have already taken locks.
CHECK(flags()->report_bugs);
CHECK(!thr->suppress_reports);
atomic_store_relaxed(&ctx->last_symbolize_time_ns, NanoTime());
const ReportDesc *rep = srep.GetReport();
CHECK_EQ(thr->current_report, nullptr);
thr->current_report = rep;
Suppression *supp = 0;
uptr pc_or_addr = 0;
for (uptr i = 0; pc_or_addr == 0 && i < rep->mops.Size(); i++)
pc_or_addr = IsSuppressed(rep->typ, rep->mops[i]->stack, &supp);
for (uptr i = 0; pc_or_addr == 0 && i < rep->stacks.Size(); i++)
pc_or_addr = IsSuppressed(rep->typ, rep->stacks[i], &supp);
for (uptr i = 0; pc_or_addr == 0 && i < rep->threads.Size(); i++)
pc_or_addr = IsSuppressed(rep->typ, rep->threads[i]->stack, &supp);
for (uptr i = 0; pc_or_addr == 0 && i < rep->locs.Size(); i++)
pc_or_addr = IsSuppressed(rep->typ, rep->locs[i], &supp);
if (pc_or_addr != 0) {
Lock lock(&ctx->fired_suppressions_mtx);
FiredSuppression s = {srep.GetReport()->typ, pc_or_addr, supp};
ctx->fired_suppressions.push_back(s);
}
{
bool old_is_freeing = thr->is_freeing;
thr->is_freeing = false;
bool suppressed = OnReport(rep, pc_or_addr != 0);
thr->is_freeing = old_is_freeing;
if (suppressed) {
thr->current_report = nullptr;
return false;
}
}
PrintReport(rep);
__tsan_on_report(rep);
ctx->nreported++;
if (flags()->halt_on_error)
Die();
thr->current_report = nullptr;
return true;
}
bool IsFiredSuppression(Context *ctx, ReportType type, StackTrace trace) {
ReadLock lock(&ctx->fired_suppressions_mtx);
for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
if (ctx->fired_suppressions[k].type != type)
continue;
for (uptr j = 0; j < trace.size; j++) {
FiredSuppression *s = &ctx->fired_suppressions[k];
if (trace.trace[j] == s->pc_or_addr) {
if (s->supp)
atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
return true;
}
}
}
return false;
}
static bool IsFiredSuppression(Context *ctx, ReportType type, uptr addr) {
ReadLock lock(&ctx->fired_suppressions_mtx);
for (uptr k = 0; k < ctx->fired_suppressions.size(); k++) {
if (ctx->fired_suppressions[k].type != type)
continue;
FiredSuppression *s = &ctx->fired_suppressions[k];
if (addr == s->pc_or_addr) {
if (s->supp)
atomic_fetch_add(&s->supp->hit_count, 1, memory_order_relaxed);
return true;
}
}
return false;
}
static bool RaceBetweenAtomicAndFree(ThreadState *thr) {
Shadow s0(thr->racy_state[0]);
Shadow s1(thr->racy_state[1]);
CHECK(!(s0.IsAtomic() && s1.IsAtomic()));
if (!s0.IsAtomic() && !s1.IsAtomic())
return true;
if (s0.IsAtomic() && s1.IsFreed())
return true;
if (s1.IsAtomic() && thr->is_freeing)
return true;
return false;
}
void ReportRace(ThreadState *thr) {
CheckedMutex::CheckNoLocks();
// Symbolizer makes lots of intercepted calls. If we try to process them,
// at best it will cause deadlocks on internal mutexes.
ScopedIgnoreInterceptors ignore;
if (!ShouldReport(thr, ReportTypeRace))
return;
if (!flags()->report_atomic_races && !RaceBetweenAtomicAndFree(thr))
return;
bool freed = false;
{
Shadow s(thr->racy_state[1]);
freed = s.GetFreedAndReset();
thr->racy_state[1] = s.raw();
}
uptr addr = ShadowToMem(thr->racy_shadow_addr);
uptr addr_min = 0;
uptr addr_max = 0;
{
uptr a0 = addr + Shadow(thr->racy_state[0]).addr0();
uptr a1 = addr + Shadow(thr->racy_state[1]).addr0();
uptr e0 = a0 + Shadow(thr->racy_state[0]).size();
uptr e1 = a1 + Shadow(thr->racy_state[1]).size();
addr_min = min(a0, a1);
addr_max = max(e0, e1);
if (IsExpectedReport(addr_min, addr_max - addr_min))
return;
}
if (HandleRacyAddress(thr, addr_min, addr_max))
return;
ReportType typ = ReportTypeRace;
if (thr->is_vptr_access && freed)
typ = ReportTypeVptrUseAfterFree;
else if (thr->is_vptr_access)
typ = ReportTypeVptrRace;
else if (freed)
typ = ReportTypeUseAfterFree;
if (IsFiredSuppression(ctx, typ, addr))
return;
const uptr kMop = 2;
VarSizeStackTrace traces[kMop];
uptr tags[kMop] = {kExternalTagNone};
uptr toppc = TraceTopPC(thr);
if (toppc >> kEventPCBits) {
// This is a work-around for a known issue.
// The scenario where this happens is rather elaborate and requires
// an instrumented __sanitizer_report_error_summary callback and
// a __tsan_symbolize_external callback and a race during a range memory
// access larger than 8 bytes. MemoryAccessRange adds the current PC to
// the trace and starts processing memory accesses. A first memory access
// triggers a race, we report it and call the instrumented
// __sanitizer_report_error_summary, which adds more stuff to the trace
// since it is intrumented. Then a second memory access in MemoryAccessRange
// also triggers a race and we get here and call TraceTopPC to get the
// current PC, however now it contains some unrelated events from the
// callback. Most likely, TraceTopPC will now return a EventTypeFuncExit
// event. Later we subtract -1 from it (in GetPreviousInstructionPc)
// and the resulting PC has kExternalPCBit set, so we pass it to
// __tsan_symbolize_external_ex. __tsan_symbolize_external_ex is within its
// rights to crash since the PC is completely bogus.
// test/tsan/double_race.cpp contains a test case for this.
toppc = 0;
}
ObtainCurrentStack(thr, toppc, &traces[0], &tags[0]);
if (IsFiredSuppression(ctx, typ, traces[0]))
return;
DynamicMutexSet mset2;
Shadow s2(thr->racy_state[1]);
RestoreStack(s2.tid(), s2.epoch(), &traces[1], mset2, &tags[1]);
if (IsFiredSuppression(ctx, typ, traces[1]))
return;
if (HandleRacyStacks(thr, traces))
return;
// If any of the accesses has a tag, treat this as an "external" race.
uptr tag = kExternalTagNone;
for (uptr i = 0; i < kMop; i++) {
if (tags[i] != kExternalTagNone) {
typ = ReportTypeExternalRace;
tag = tags[i];
break;
}
}
ThreadRegistryLock l0(&ctx->thread_registry);
ScopedReport rep(typ, tag);
for (uptr i = 0; i < kMop; i++) {
Shadow s(thr->racy_state[i]);
rep.AddMemoryAccess(addr, tags[i], s, traces[i],
i == 0 ? &thr->mset : mset2);
}
for (uptr i = 0; i < kMop; i++) {
FastState s(thr->racy_state[i]);
ThreadContext *tctx = static_cast<ThreadContext *>(
ctx->thread_registry.GetThreadLocked(s.tid()));
if (s.epoch() < tctx->epoch0 || s.epoch() > tctx->epoch1)
continue;
rep.AddThread(tctx);
}
rep.AddLocation(addr_min, addr_max - addr_min);
#if !SANITIZER_GO
{
Shadow s(thr->racy_state[1]);
if (s.epoch() <= thr->last_sleep_clock.get(s.tid()))
rep.AddSleep(thr->last_sleep_stack_id);
}
#endif
OutputReport(thr, rep);
}
void PrintCurrentStack(ThreadState *thr, uptr pc) {
VarSizeStackTrace trace;
ObtainCurrentStack(thr, pc, &trace);
PrintStack(SymbolizeStack(trace));
}
// Always inlining PrintCurrentStackSlow, because LocatePcInTrace assumes
// __sanitizer_print_stack_trace exists in the actual unwinded stack, but
// tail-call to PrintCurrentStackSlow breaks this assumption because
// __sanitizer_print_stack_trace disappears after tail-call.
// However, this solution is not reliable enough, please see dvyukov's comment
// http://reviews.llvm.org/D19148#406208
// Also see PR27280 comment 2 and 3 for breaking examples and analysis.
ALWAYS_INLINE USED void PrintCurrentStackSlow(uptr pc) {
#if !SANITIZER_GO
uptr bp = GET_CURRENT_FRAME();
auto *ptrace = New<BufferedStackTrace>();
ptrace->Unwind(pc, bp, nullptr, false);
for (uptr i = 0; i < ptrace->size / 2; i++) {
uptr tmp = ptrace->trace_buffer[i];
ptrace->trace_buffer[i] = ptrace->trace_buffer[ptrace->size - i - 1];
ptrace->trace_buffer[ptrace->size - i - 1] = tmp;
}
PrintStack(SymbolizeStack(*ptrace));
#endif
}
} // namespace __tsan
using namespace __tsan;
extern "C" {
SANITIZER_INTERFACE_ATTRIBUTE
void __sanitizer_print_stack_trace() {
PrintCurrentStackSlow(StackTrace::GetCurrentPc());
}
} // extern "C"
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