[PATCH] D101881: [hwasan] Fix missing synchronization in AllocThread.
Evgenii Stepanov via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue May 4 19:51:59 PDT 2021
eugenis created this revision.
eugenis added reviewers: vitalybuka, pcc, hctim.
eugenis requested review of this revision.
Herald added a project: Sanitizers.
Herald added a subscriber: Sanitizers.
The problem was introduced in D100348 <https://reviews.llvm.org/D100348>.
It's really hard to trigger the bug in a stress test - the race is just too
narrow - but the new checks in Thread::Init should at least provide usable
diagnostic if the problem ever returns.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D101881
Files:
compiler-rt/lib/hwasan/hwasan_thread.cpp
compiler-rt/lib/hwasan/hwasan_thread_list.h
Index: compiler-rt/lib/hwasan/hwasan_thread_list.h
===================================================================
--- compiler-rt/lib/hwasan/hwasan_thread_list.h
+++ compiler-rt/lib/hwasan/hwasan_thread_list.h
@@ -173,6 +173,7 @@
private:
Thread *AllocThread() {
+ SpinMutexLock l(&free_space_mutex_);
uptr align = ring_buffer_size_ * 2;
CHECK(IsAligned(free_space_, align));
Thread *t = (Thread *)(free_space_ + ring_buffer_size_);
@@ -181,6 +182,7 @@
return t;
}
+ SpinMutex free_space_mutex_;
uptr free_space_;
uptr free_space_end_;
uptr ring_buffer_size_;
Index: compiler-rt/lib/hwasan/hwasan_thread.cpp
===================================================================
--- compiler-rt/lib/hwasan/hwasan_thread.cpp
+++ compiler-rt/lib/hwasan/hwasan_thread.cpp
@@ -35,6 +35,10 @@
}
void Thread::Init(uptr stack_buffer_start, uptr stack_buffer_size) {
+ CHECK_EQ(0, unique_id_); // try to catch bad stack reuse
+ CHECK_EQ(0, stack_top_);
+ CHECK_EQ(0, stack_bottom_);
+
static u64 unique_id;
unique_id_ = unique_id++;
if (auto sz = flags()->heap_history_size)
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