tsan: lock internal allocator around fork
There is a small chance that the internal allocator is locked
during fork and then the new process is created with locked
internal allocator and any attempts to use it will deadlock.
For example, if detected a suppressed race in the parent during fork
and then another suppressed race after the fork.
This becomes much more likely with the new tsan runtime
as it uses the internal allocator for more things.
Reviewed By: melver
Differential Revision: https://reviews.llvm.org/D114531
GitOrigin-RevId: 348389263ca545f0dd71aea505c595331d2a07c5
diff --git a/lib/sanitizer_common/sanitizer_allocator.cpp b/lib/sanitizer_common/sanitizer_allocator.cpp
index 3c04289..af0b094 100644
--- a/lib/sanitizer_common/sanitizer_allocator.cpp
+++ b/lib/sanitizer_common/sanitizer_allocator.cpp
@@ -125,6 +125,16 @@
RawInternalFree(addr, cache);
}
+void InternalAllocatorLock() NO_THREAD_SAFETY_ANALYSIS {
+ internal_allocator_cache_mu.Lock();
+ internal_allocator()->ForceLock();
+}
+
+void InternalAllocatorUnlock() NO_THREAD_SAFETY_ANALYSIS {
+ internal_allocator()->ForceUnlock();
+ internal_allocator_cache_mu.Unlock();
+}
+
// LowLevelAllocator
constexpr uptr kLowLevelAllocatorDefaultAlignment = 8;
static uptr low_level_alloc_min_alignment = kLowLevelAllocatorDefaultAlignment;
diff --git a/lib/sanitizer_common/sanitizer_allocator_internal.h b/lib/sanitizer_common/sanitizer_allocator_internal.h
index 3284903..3899473 100644
--- a/lib/sanitizer_common/sanitizer_allocator_internal.h
+++ b/lib/sanitizer_common/sanitizer_allocator_internal.h
@@ -48,6 +48,8 @@
void *InternalCalloc(uptr count, uptr size,
InternalAllocatorCache *cache = nullptr);
void InternalFree(void *p, InternalAllocatorCache *cache = nullptr);
+void InternalAllocatorLock();
+void InternalAllocatorUnlock();
InternalAllocator *internal_allocator();
} // namespace __sanitizer
diff --git a/lib/tsan/rtl/tsan_mman.cpp b/lib/tsan/rtl/tsan_mman.cpp
index ef97ad0..8f87fff 100644
--- a/lib/tsan/rtl/tsan_mman.cpp
+++ b/lib/tsan/rtl/tsan_mman.cpp
@@ -110,6 +110,16 @@
gp->mtx.Unlock();
}
+void AllocatorLock() NO_THREAD_SAFETY_ANALYSIS {
+ global_proc()->mtx.Lock();
+ InternalAllocatorLock();
+}
+
+void AllocatorUnlock() NO_THREAD_SAFETY_ANALYSIS {
+ InternalAllocatorUnlock();
+ global_proc()->mtx.Unlock();
+}
+
static constexpr uptr kMaxAllowedMallocSize = 1ull << 40;
static uptr max_user_defined_malloc_size;
diff --git a/lib/tsan/rtl/tsan_mman.h b/lib/tsan/rtl/tsan_mman.h
index efea5e5..db8488e 100644
--- a/lib/tsan/rtl/tsan_mman.h
+++ b/lib/tsan/rtl/tsan_mman.h
@@ -24,6 +24,8 @@
void AllocatorProcStart(Processor *proc);
void AllocatorProcFinish(Processor *proc);
void AllocatorPrintStats();
+void AllocatorLock();
+void AllocatorUnlock();
// For user allocations.
void *user_alloc_internal(ThreadState *thr, uptr pc, uptr sz,
diff --git a/lib/tsan/rtl/tsan_rtl.cpp b/lib/tsan/rtl/tsan_rtl.cpp
index 8126a50..4e45042 100644
--- a/lib/tsan/rtl/tsan_rtl.cpp
+++ b/lib/tsan/rtl/tsan_rtl.cpp
@@ -494,6 +494,7 @@
ctx->thread_registry.Lock();
ctx->report_mtx.Lock();
ScopedErrorReportLock::Lock();
+ AllocatorLock();
// Suppress all reports in the pthread_atfork callbacks.
// Reports will deadlock on the report_mtx.
// We could ignore sync operations as well,
@@ -512,6 +513,7 @@
void ForkParentAfter(ThreadState *thr, uptr pc) NO_THREAD_SAFETY_ANALYSIS {
thr->suppress_reports--; // Enabled in ForkBefore.
thr->ignore_interceptors--;
+ AllocatorUnlock();
ScopedErrorReportLock::Unlock();
ctx->report_mtx.Unlock();
ctx->thread_registry.Unlock();
@@ -521,6 +523,7 @@
bool start_thread) NO_THREAD_SAFETY_ANALYSIS {
thr->suppress_reports--; // Enabled in ForkBefore.
thr->ignore_interceptors--;
+ AllocatorUnlock();
ScopedErrorReportLock::Unlock();
ctx->report_mtx.Unlock();
ctx->thread_registry.Unlock();
@@ -755,7 +758,7 @@
{MutexInvalid, "Invalid", {}},
{MutexThreadRegistry, "ThreadRegistry", {}},
{MutexTypeTrace, "Trace", {MutexLeaf}},
- {MutexTypeReport, "Report", {MutexTypeSyncVar}},
+ {MutexTypeReport, "Report", {MutexTypeSyncVar, MutexTypeGlobalProc}},
{MutexTypeSyncVar, "SyncVar", {}},
{MutexTypeAnnotations, "Annotations", {}},
{MutexTypeAtExit, "AtExit", {MutexTypeSyncVar}},
