From 0fb14e944c739baba542882ce1504d00da25c9f7 Mon Sep 17 00:00:00 2001 From: Kuba Mracek Date: Fri, 13 Apr 2018 00:29:24 +0000 Subject: [PATCH] [asan] Reduce flakiness in stack-overflow detection IsStackOverflow only treats accesses within 512 bytes of SP as stack-overflow. This should really be the size of a page instead. The scariness_score_test.cc triggers stack overflow with frames that are even larger than a page, which can also trigger a fault that will not be recognized as stack-overflow. Let's just use smaller frames. llvm-svn: 329980 --- compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc | 4 +++- compiler-rt/test/asan/TestCases/scariness_score_test.cc | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc index 7fbb939..e757600 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc +++ b/compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cc @@ -230,7 +230,9 @@ bool SignalContext::IsStackOverflow() const { // take it into account. bool IsStackAccess = addr >= (sp & ~0xFFF) && addr < sp + 0xFFFF; #else - bool IsStackAccess = addr + 512 > sp && addr < sp + 0xFFFF; + // Let's accept up to a page size away from top of stack. Things like stack + // probing can trigger accesses with such large offsets. + bool IsStackAccess = addr + GetPageSizeCached() > sp && addr < sp + 0xFFFF; #endif #if __powerpc__ diff --git a/compiler-rt/test/asan/TestCases/scariness_score_test.cc b/compiler-rt/test/asan/TestCases/scariness_score_test.cc index 171bea9..fb174eb 100644 --- a/compiler-rt/test/asan/TestCases/scariness_score_test.cc +++ b/compiler-rt/test/asan/TestCases/scariness_score_test.cc @@ -115,7 +115,7 @@ void DoubleFree() { } void StackOverflow(int Idx) { - int some_stack[10000]; + int some_stack[256]; static volatile int *x; x = &some_stack[0]; if (Idx > 0) -- 2.7.4