Merging r367442:

------------------------------------------------------------------------
r367442 | arichardson | 2019-07-31 18:31:55 +0200 (Wed, 31 Jul 2019) | 30 lines

[Sanitizer][ASAN][MSAN] Fix infinite recursion on FreeBSD

Summary:
MSAN was broken on FreeBSD by https://reviews.llvm.org/D55703: after this
change accesses to the key variable call __tls_get_addr, which is
intercepted. The interceptor then calls GetCurrentThread which calls
MsanTSDGet which again calls __tls_get_addr, etc...
Using the default implementation in the SANITIZER_FREEBSD case fixes MSAN
for me.

I then applied the same change to ASAN (introduced in https://reviews.llvm.org/D55596)
but that did not work yet. In the ASAN case, we get infinite recursion
again during initialization, this time because calling pthread_key_create() early on
results in infinite recursion. pthread_key_create() calls sysctlbyname()
which is intercepted but COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED returns
true, so the interceptor calls internal_sysctlbyname() which then ends up
calling the interceptor again. I fixed this issue by using dlsym() to get
the libc version of sysctlbyname() instead.

This fixes https://llvm.org/PR40761

Reviewers: vitalybuka, krytarowski, devnexen, dim, bsdjhb, #sanitizers, MaskRay

Reviewed By: MaskRay

Subscribers: MaskRay, emaste, kubamracek, jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D65221
------------------------------------------------------------------------

llvm-svn: 367524

compiler-rt/lib/asan/asan_posix.cc

@@ -39,8 +39,8 @@ void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
 
 // ---------------------- TSD ---------------- {{{1
 
-#if SANITIZER_NETBSD || SANITIZER_FREEBSD
-// Thread Static Data cannot be used in early init on NetBSD and FreeBSD.
+#if SANITIZER_NETBSD
+// Thread Static Data cannot be used in early init on NetBSD.
 // Reuse the Asan TSD API for compatibility with existing code
 // with an alternative implementation.
 

compiler-rt/lib/msan/msan_linux.cc

@@ -174,8 +174,8 @@ void InstallAtExitHandler() {
 
 // ---------------------- TSD ---------------- {{{1
 
-#if SANITIZER_NETBSD || SANITIZER_FREEBSD
-// Thread Static Data cannot be used in early init on NetBSD and FreeBSD.
+#if SANITIZER_NETBSD
+// Thread Static Data cannot be used in early init on NetBSD.
 // Reuse the MSan TSD API for compatibility with existing code
 // with an alternative implementation.
 

compiler-rt/lib/sanitizer_common/sanitizer_linux.cc

@@ -779,7 +779,11 @@ int internal_sysctl(const int *name, unsigned int namelen, void *oldp,
 #if SANITIZER_FREEBSD
 int internal_sysctlbyname(const char *sname, void *oldp, uptr *oldlenp,
                           const void *newp, uptr newlen) {
-  return sysctlbyname(sname, oldp, (size_t *)oldlenp, newp, (size_t)newlen);
+  static decltype(sysctlbyname) *real = nullptr;
+  if (!real)
+    real = (decltype(sysctlbyname) *)dlsym(RTLD_NEXT, "sysctlbyname");
+  CHECK(real);
+  return real(sname, oldp, (size_t *)oldlenp, newp, (size_t)newlen);
 }
 #endif
 #endif

compiler-rt/test/asan/TestCases/Posix/fread_fwrite.cc

@@ -1,9 +1,6 @@
 // RUN: %clangxx_asan -g %s -o %t
 // RUN: not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-FWRITE
 // RUN: not %run %t 1 2>&1 | FileCheck %s --check-prefix=CHECK-FREAD
-//
-// On FreeBSD stack overflow error instead
-// XFAIL: freebsd
 
 #include <stdio.h>
 #include <stdlib.h>

compiler-rt/test/asan/TestCases/Posix/tsd_dtor_leak.cc

@@ -3,8 +3,6 @@
 // RUN: %clangxx_asan -O1 %s -pthread -o %t
 // RUN: %env_asan_opts=quarantine_size_mb=0 %run %t
 // XFAIL: x86_64-netbsd
-// Assertion fails
-// XFAIL: x86_64-freebsd
 #include <pthread.h>
 #include <stdio.h>
 #include <stdlib.h>

compiler-rt/test/msan/tzset.cc

@@ -1,5 +1,4 @@
 // RUN: %clangxx_msan -O0 %s -o %t && %run %t
-// XFAIL: freebsd
 
 #include <stdlib.h>
 #include <string.h>