From 827ea206c1078fc7c7da287984a7ba4563390589 Mon Sep 17 00:00:00 2001
From: Maxim Ostapenko <m.ostapenko@partner.samsung.com>
Date: Fri, 23 Sep 2016 07:40:55 +0000
Subject: [msan] Prevent initialization failure with newer (2.23+) glibc in
 use.

This patch is pretty the same as http://reviews.llvm.org/D20235 that we used
for ASan. Using the same hack for MSan fixes its initialization with newer
Glibc in use.

Differential Revision: https://reviews.llvm.org/D24736


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@282232 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/msan/msan_interceptors.cc | 43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

(limited to 'lib/msan')

diff --git a/lib/msan/msan_interceptors.cc b/lib/msan/msan_interceptors.cc
index f23d3eeb3..2aeaef49e 100644
--- a/lib/msan/msan_interceptors.cc
+++ b/lib/msan/msan_interceptors.cc
@@ -64,6 +64,23 @@ bool IsInInterceptorScope() {
   return in_interceptor_scope;
 }
 
+static uptr allocated_for_dlsym;
+static const uptr kDlsymAllocPoolSize = 1024;
+static uptr alloc_memory_for_dlsym[kDlsymAllocPoolSize];
+
+static bool IsInDlsymAllocPool(const void *ptr) {
+  uptr off = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+  return off < sizeof(alloc_memory_for_dlsym);
+}
+
+static void *AllocateFromLocalPool(uptr size_in_bytes) {
+  uptr size_in_words = RoundUpTo(size_in_bytes, kWordSize) / kWordSize;
+  void *mem = (void *)&alloc_memory_for_dlsym[allocated_for_dlsym];
+  allocated_for_dlsym += size_in_words;
+  CHECK_LT(allocated_for_dlsym, kDlsymAllocPoolSize);
+  return mem;
+}
+
 #define ENSURE_MSAN_INITED() do { \
   CHECK(!msan_init_is_running); \
   if (!msan_inited) { \
@@ -227,14 +244,14 @@ INTERCEPTOR(void *, pvalloc, SIZE_T size) {
 
 INTERCEPTOR(void, free, void *ptr) {
   GET_MALLOC_STACK_TRACE;
-  if (!ptr) return;
+  if (!ptr || UNLIKELY(IsInDlsymAllocPool(ptr))) return;
   MsanDeallocate(&stack, ptr);
 }
 
 #if !SANITIZER_FREEBSD
 INTERCEPTOR(void, cfree, void *ptr) {
   GET_MALLOC_STACK_TRACE;
-  if (!ptr) return;
+  if (!ptr || UNLIKELY(IsInDlsymAllocPool(ptr))) return;
   MsanDeallocate(&stack, ptr);
 }
 #define MSAN_MAYBE_INTERCEPT_CFREE INTERCEPT_FUNCTION(cfree)
@@ -907,27 +924,29 @@ INTERCEPTOR(int, epoll_pwait, int epfd, void *events, int maxevents,
 
 INTERCEPTOR(void *, calloc, SIZE_T nmemb, SIZE_T size) {
   GET_MALLOC_STACK_TRACE;
-  if (UNLIKELY(!msan_inited)) {
+  if (UNLIKELY(!msan_inited))
     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
-    const SIZE_T kCallocPoolSize = 1024;
-    static uptr calloc_memory_for_dlsym[kCallocPoolSize];
-    static SIZE_T allocated;
-    SIZE_T size_in_words = ((nmemb * size) + kWordSize - 1) / kWordSize;
-    void *mem = (void*)&calloc_memory_for_dlsym[allocated];
-    allocated += size_in_words;
-    CHECK(allocated < kCallocPoolSize);
-    return mem;
-  }
+    return AllocateFromLocalPool(nmemb * size);
   return MsanCalloc(&stack, nmemb, size);
 }
 
 INTERCEPTOR(void *, realloc, void *ptr, SIZE_T size) {
   GET_MALLOC_STACK_TRACE;
+  if (UNLIKELY(IsInDlsymAllocPool(ptr))) {
+    uptr offset = (uptr)ptr - (uptr)alloc_memory_for_dlsym;
+    uptr copy_size = Min(size, kDlsymAllocPoolSize - offset);
+    void *new_ptr = AllocateFromLocalPool(size);
+    internal_memcpy(new_ptr, ptr, copy_size);
+    return new_ptr;
+  }
   return MsanReallocate(&stack, ptr, size, sizeof(u64), false);
 }
 
 INTERCEPTOR(void *, malloc, SIZE_T size) {
   GET_MALLOC_STACK_TRACE;
+  if (UNLIKELY(!msan_inited))
+    // Hack: dlsym calls malloc before REAL(malloc) is retrieved from dlsym.
+    return AllocateFromLocalPool(size);
   return MsanReallocate(&stack, nullptr, size, sizeof(u64), false);
 }
 
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