[compiler-rt] r367442 - [Sanitizer][ASAN][MSAN] Fix infinite recursion on FreeBSD

Thu Aug 1 01:32:07 PDT 2019

Merged to release_90 in r367524. Please let me know if there are any follow-ups.

On Wed, Jul 31, 2019 at 6:31 PM Alexander Richardson via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
> Author: arichardson
> Date: Wed Jul 31 09:31:55 2019
> New Revision: 367442
>
> URL: http://llvm.org/viewvc/llvm-project?rev=367442&view=rev
> Log:
> [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
>
> Modified:
>     compiler-rt/trunk/lib/asan/asan_posix.cc
>     compiler-rt/trunk/lib/msan/msan_linux.cc
>     compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
>     compiler-rt/trunk/test/asan/TestCases/Posix/fread_fwrite.cc
>     compiler-rt/trunk/test/asan/TestCases/Posix/tsd_dtor_leak.cc
>     compiler-rt/trunk/test/msan/tzset.cc
>
> Modified: compiler-rt/trunk/lib/asan/asan_posix.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_posix.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/asan/asan_posix.cc (original)
> +++ compiler-rt/trunk/lib/asan/asan_posix.cc Wed Jul 31 09:31:55 2019
> @@ -39,8 +39,8 @@ void AsanOnDeadlySignal(int signo, void
>
>  // ---------------------- 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.
>
>
> Modified: compiler-rt/trunk/lib/msan/msan_linux.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_linux.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/msan/msan_linux.cc (original)
> +++ compiler-rt/trunk/lib/msan/msan_linux.cc Wed Jul 31 09:31:55 2019
> @@ -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.
>
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_linux.cc Wed Jul 31 09:31:55 2019
> @@ -779,7 +779,11 @@ int internal_sysctl(const int *name, uns
>  #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
>
> Modified: compiler-rt/trunk/test/asan/TestCases/Posix/fread_fwrite.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Posix/fread_fwrite.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/asan/TestCases/Posix/fread_fwrite.cc (original)
> +++ compiler-rt/trunk/test/asan/TestCases/Posix/fread_fwrite.cc Wed Jul 31 09:31:55 2019
> @@ -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>
>
> Modified: compiler-rt/trunk/test/asan/TestCases/Posix/tsd_dtor_leak.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/asan/TestCases/Posix/tsd_dtor_leak.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/asan/TestCases/Posix/tsd_dtor_leak.cc (original)
> +++ compiler-rt/trunk/test/asan/TestCases/Posix/tsd_dtor_leak.cc Wed Jul 31 09:31:55 2019
> @@ -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>
>
> Modified: compiler-rt/trunk/test/msan/tzset.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/msan/tzset.cc?rev=367442&r1=367441&r2=367442&view=diff
> ==============================================================================
> --- compiler-rt/trunk/test/msan/tzset.cc (original)
> +++ compiler-rt/trunk/test/msan/tzset.cc Wed Jul 31 09:31:55 2019
> @@ -1,5 +1,4 @@
>  // RUN: %clangxx_msan -O0 %s -o %t && %run %t
> -// XFAIL: freebsd
>
>  #include <stdlib.h>
>  #include <string.h>
>
>
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