[PATCH] D95183: [LSan] Introduce a callback mechanism to allow adding data reachable from ThreadContexts to the frontier.
Dan Liew via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 21 16:18:29 PST 2021
delcypher created this revision.
delcypher added reviewers: kubamracek, yln, kcc, dvyukov, eugenis, vitalybuka, cryptoad, earthdok.
delcypher requested review of this revision.
Herald added a project: Sanitizers.
Herald added a subscriber: Sanitizers.
This mechanism is intended to provide a way to treat the `arg` pointer
of a created (but not yet started) thread as reachable. In future
patches this will be implemented in `ForEachRegisteredThreadContextCb`.
A separate implementation of `ForEachRegisteredThreadContextCb` exists
for ASan and LSan runtimes because they need to be implemented
differently in future patches.
rdar://problem/63537240
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D95183
Files:
compiler-rt/lib/asan/asan_allocator.cpp
compiler-rt/lib/lsan/lsan_common.cpp
compiler-rt/lib/lsan/lsan_common.h
compiler-rt/lib/lsan/lsan_thread.cpp
Index: compiler-rt/lib/lsan/lsan_thread.cpp
===================================================================
--- compiler-rt/lib/lsan/lsan_thread.cpp
+++ compiler-rt/lib/lsan/lsan_thread.cpp
@@ -112,4 +112,13 @@
return thread_registry;
}
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg) {
+ // This function can be used to treat memory reachable from `tctx` as live.
+ // This is useful for threads that have been created but not yet started.
+
+ // This is currently a no-op because the LSan `pthread_create()` interceptor
+ // blocks until the child thread starts which keeps the thread's `arg` pointer
+ // live.
+}
+
} // namespace __lsan
Index: compiler-rt/lib/lsan/lsan_common.h
===================================================================
--- compiler-rt/lib/lsan/lsan_common.h
+++ compiler-rt/lib/lsan/lsan_common.h
@@ -20,6 +20,7 @@
#include "sanitizer_common/sanitizer_platform.h"
#include "sanitizer_common/sanitizer_stoptheworld.h"
#include "sanitizer_common/sanitizer_symbolizer.h"
+#include "sanitizer_common/sanitizer_thread_registry.h"
// LeakSanitizer relies on some Glibc's internals (e.g. TLS machinery) on Linux.
// Also, LSan doesn't like 32 bit architectures
@@ -142,6 +143,7 @@
void ScanRootRegion(Frontier *frontier, RootRegion const ®ion,
uptr region_begin, uptr region_end, bool is_readable);
void ForEachExtraStackRangeCb(uptr begin, uptr end, void* arg);
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg);
// Run stoptheworld while holding any platform-specific locks, as well as the
// allocator and thread registry locks.
void LockStuffAndStopTheWorld(StopTheWorldCallback callback,
Index: compiler-rt/lib/lsan/lsan_common.cpp
===================================================================
--- compiler-rt/lib/lsan/lsan_common.cpp
+++ compiler-rt/lib/lsan/lsan_common.cpp
@@ -520,6 +520,11 @@
ForEachChunk(MarkInvalidPCCb, &arg);
}
+void ProcessThreadRegistry(Frontier *frontier) {
+ GetThreadRegistryLocked()->RunCallbackForEachThreadLocked(
+ ForEachRegisteredThreadContextCb, frontier);
+}
+
// Sets the appropriate tag on each chunk.
static void ClassifyAllChunks(SuspendedThreadsList const &suspended_threads,
Frontier *frontier) {
@@ -532,6 +537,7 @@
ForEachChunk(CollectIgnoredCb, frontier);
ProcessGlobalRegions(frontier);
ProcessThreads(suspended_threads, frontier);
+ ProcessThreadRegistry(frontier);
ProcessRootRegions(frontier);
FloodFillTag(frontier, kReachable);
Index: compiler-rt/lib/asan/asan_allocator.cpp
===================================================================
--- compiler-rt/lib/asan/asan_allocator.cpp
+++ compiler-rt/lib/asan/asan_allocator.cpp
@@ -1124,6 +1124,15 @@
return 0;
}
+void ForEachRegisteredThreadContextCb(ThreadContextBase *tctx, void *arg) {
+ // This function can be used to treat memory reachable from `tctx` as live.
+ // This is useful for threads that have been created but not yet started.
+
+ // This is currently a no-op because the ASan `pthread_create()` interceptor
+ // blocks until the child thread starts which keeps the thread's `arg` pointer
+ // live.
+}
+
uptr GetUserBegin(uptr chunk) {
__asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(chunk);
return m ? m->Beg() : 0;
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