[compiler-rt] r189351 - [msan] Save/restore va_arg_overflow_tls in signal handlers.
Evgeniy Stepanov
eugeni.stepanov at gmail.com
Tue Aug 27 07:08:15 PDT 2013
Author: eugenis
Date: Tue Aug 27 09:08:15 2013
New Revision: 189351
URL: http://llvm.org/viewvc/llvm-project?rev=189351&view=rev
Log:
[msan] Save/restore va_arg_overflow_tls in signal handlers.
Modified:
compiler-rt/trunk/lib/msan/lit_tests/signal_stress_test.cc
compiler-rt/trunk/lib/msan/msan.cc
compiler-rt/trunk/lib/msan/msan.h
compiler-rt/trunk/lib/msan/msan_interceptors.cc
Modified: compiler-rt/trunk/lib/msan/lit_tests/signal_stress_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/lit_tests/signal_stress_test.cc?rev=189351&r1=189350&r2=189351&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/lit_tests/signal_stress_test.cc (original)
+++ compiler-rt/trunk/lib/msan/lit_tests/signal_stress_test.cc Tue Aug 27 09:08:15 2013
@@ -1,4 +1,4 @@
-// RUN: %clangxx_msan -O0 %s -o %t && %t
+// RUN: %clangxx_msan -std=c++11 -O0 %s -o %t && %t
// Test that va_arg shadow from a signal handler does not leak outside.
@@ -9,19 +9,14 @@
#include <sys/time.h>
#include <stdio.h>
-const int kArgCnt = 20;
-const int kSigCnt = 100;
+const int kSigCnt = 200;
-volatile int z;
-
-void f(bool poisoned, ...) {
+void f(bool poisoned, int n, ...) {
va_list vl;
- va_start(vl, poisoned);
- for (int i = 0; i < kArgCnt; ++i) {
+ va_start(vl, n);
+ for (int i = 0; i < n; ++i) {
void *p = va_arg(vl, void *);
- if (poisoned)
- assert(__msan_test_shadow(&p, sizeof(p)) == 0);
- else
+ if (!poisoned)
assert(__msan_test_shadow(&p, sizeof(p)) == -1);
}
va_end(vl);
@@ -32,13 +27,10 @@ int sigcnt;
void SignalHandler(int signo) {
assert(signo == SIGPROF);
void *p;
- void ** volatile q = &p;
- f(true,
- *q, *q, *q, *q, *q,
- *q, *q, *q, *q, *q,
- *q, *q, *q, *q, *q,
- *q, *q, *q, *q, *q,
- *q, *q, *q, *q, *q);
+ void **volatile q = &p;
+ f(true, 10,
+ *q, *q, *q, *q, *q,
+ *q, *q, *q, *q, *q);
++sigcnt;
}
@@ -52,12 +44,20 @@ int main() {
itv.it_value.tv_usec = 100;
setitimer(ITIMER_PROF, &itv, NULL);
+ void *p;
+ void **volatile q = &p;
+
do {
- f(false,
- 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0);
+ f(false, 20,
+ nullptr, nullptr, nullptr, nullptr, nullptr,
+ nullptr, nullptr, nullptr, nullptr, nullptr,
+ nullptr, nullptr, nullptr, nullptr, nullptr,
+ nullptr, nullptr, nullptr, nullptr, nullptr);
+ f(true, 20,
+ *q, *q, *q, *q, *q,
+ *q, *q, *q, *q, *q,
+ *q, *q, *q, *q, *q,
+ *q, *q, *q, *q, *q);
} while (sigcnt < kSigCnt);
itv.it_interval.tv_sec = 0;
Modified: compiler-rt/trunk/lib/msan/msan.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan.cc?rev=189351&r1=189350&r2=189351&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan.cc (original)
+++ compiler-rt/trunk/lib/msan/msan.cc Tue Aug 27 09:08:15 2013
@@ -230,11 +230,29 @@ void UnpoisonParam(uptr n) {
internal_memset(__msan_param_tls, 0, n * sizeof(*__msan_param_tls));
}
-void UnpoisonThreadLocalState() {
+// Backup MSan runtime TLS state.
+// Implementation must be async-signal-safe.
+// Instances of this class may live on the signal handler stack, and data size
+// may be an issue.
+void ScopedThreadLocalStateBackup::Backup() {
+ va_arg_overflow_size_tls = __msan_va_arg_overflow_size_tls;
+}
+
+void ScopedThreadLocalStateBackup::Restore() {
+ // A lame implementation that only keeps essential state and resets the rest.
+ __msan_va_arg_overflow_size_tls = va_arg_overflow_size_tls;
+
internal_memset(__msan_param_tls, 0, sizeof(__msan_param_tls));
internal_memset(__msan_retval_tls, 0, sizeof(__msan_retval_tls));
internal_memset(__msan_va_arg_tls, 0, sizeof(__msan_va_arg_tls));
- __msan_va_arg_overflow_size_tls = 0;
+
+ if (__msan_get_track_origins()) {
+ internal_memset(&__msan_retval_origin_tls, 0, sizeof(__msan_retval_tls));
+ internal_memset(__msan_param_origin_tls, 0, sizeof(__msan_param_origin_tls));
+ }
+}
+
+void UnpoisonThreadLocalState() {
}
} // namespace __msan
Modified: compiler-rt/trunk/lib/msan/msan.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan.h?rev=189351&r1=189350&r2=189351&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan.h (original)
+++ compiler-rt/trunk/lib/msan/msan.h Tue Aug 27 09:08:15 2013
@@ -86,6 +86,15 @@ void UnpoisonThreadLocalState();
StackTrace::GetCurrentPc(), GET_CURRENT_FRAME(), \
common_flags()->fast_unwind_on_malloc)
+class ScopedThreadLocalStateBackup {
+public:
+ ScopedThreadLocalStateBackup() { Backup(); }
+ ~ScopedThreadLocalStateBackup() { Restore(); }
+ void Backup();
+ void Restore();
+private:
+ u64 va_arg_overflow_size_tls;
+};
} // namespace __msan
#define MSAN_MALLOC_HOOK(ptr, size) \
Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_interceptors.cc?rev=189351&r1=189350&r2=189351&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_interceptors.cc Tue Aug 27 09:08:15 2013
@@ -911,17 +911,20 @@ static atomic_uintptr_t sigactions[kMaxS
static StaticSpinMutex sigactions_mu;
static void SignalHandler(int signo) {
+ ScopedThreadLocalStateBackup stlsb;
+ stlsb.Backup();
UnpoisonParam(1);
typedef void (*signal_cb)(int x);
signal_cb cb =
(signal_cb)atomic_load(&sigactions[signo], memory_order_relaxed);
cb(signo);
-
- UnpoisonThreadLocalState();
+ stlsb.Restore();
}
static void SignalAction(int signo, void *si, void *uc) {
+ ScopedThreadLocalStateBackup stlsb;
+ stlsb.Backup();
UnpoisonParam(3);
__msan_unpoison(si, sizeof(__sanitizer_sigaction));
__msan_unpoison(uc, __sanitizer::ucontext_t_sz);
@@ -930,8 +933,7 @@ static void SignalAction(int signo, void
sigaction_cb cb =
(sigaction_cb)atomic_load(&sigactions[signo], memory_order_relaxed);
cb(signo, si, uc);
-
- UnpoisonThreadLocalState();
+ stlsb.Restore();
}
INTERCEPTOR(int, sigaction, int signo, const __sanitizer_sigaction *act,
More information about the llvm-commits
mailing list