[PATCH] D34243: [Sanitizers] Secondary allocator respects allocator_may_return_null=1.

[Aleksey Shlyapnikov via Phabricator via llvm-commits]

alekseyshl created this revision.
Herald added a subscriber: kubamracek.

Context: https://github.com/google/sanitizers/issues/740.

Making secondary allocator to respect allocator_may_return_null=1 flag
and return nullptr when "out of memory" happens.

More changes in primary allocator and operator new will follow.


https://reviews.llvm.org/D34243

Files:
  lib/sanitizer_common/sanitizer_allocator_secondary.h
  lib/sanitizer_common/sanitizer_common.h
  lib/sanitizer_common/sanitizer_posix.cc
  lib/sanitizer_common/sanitizer_win.cc


Index: lib/sanitizer_common/sanitizer_win.cc
===================================================================
--- lib/sanitizer_common/sanitizer_win.cc
+++ lib/sanitizer_common/sanitizer_win.cc
@@ -131,6 +131,16 @@
   }
 }
 
+void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
+  void *rv = VirtualAlloc(0, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
+  if (rv == 0) {
+    error_t last_error = GetLastError();
+    if (last_error != ERROR_NOT_ENOUGH_MEMORY)
+      ReportMmapFailureAndDie(size, mem_type, "allocate", last_error);
+  }
+  return rv;
+}
+
 // We want to map a chunk of address space aligned to 'alignment'.
 void *MmapAlignedOrDie(uptr size, uptr alignment, const char *mem_type) {
   CHECK(IsPowerOfTwo(size));
Index: lib/sanitizer_common/sanitizer_posix.cc
===================================================================
--- lib/sanitizer_common/sanitizer_posix.cc
+++ lib/sanitizer_common/sanitizer_posix.cc
@@ -22,6 +22,7 @@
 #include "sanitizer_procmaps.h"
 #include "sanitizer_stacktrace.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <sys/mman.h>
@@ -145,6 +146,21 @@
   DecreaseTotalMmap(size);
 }
 
+void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
+  size = RoundUpTo(size, GetPageSizeCached());
+  uptr res = internal_mmap(nullptr, size,
+                           PROT_READ | PROT_WRITE,
+                           MAP_PRIVATE | MAP_ANON, -1, 0);
+  int reserrno;
+  if (internal_iserror(res, &reserrno)) {
+    if (reserrno == ENOMEM)
+      return nullptr;
+    ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
+  }
+  IncreaseTotalMmap(size);
+  return (void *)res;
+}
+
 // We want to map a chunk of address space aligned to 'alignment'.
 // We do it by maping a bit more and then unmaping redundant pieces.
 // We probably can do it with fewer syscalls in some OS-dependent way.
Index: lib/sanitizer_common/sanitizer_common.h
===================================================================
--- lib/sanitizer_common/sanitizer_common.h
+++ lib/sanitizer_common/sanitizer_common.h
@@ -85,6 +85,9 @@
   return MmapOrDie(size, mem_type, /*raw_report*/ true);
 }
 void UnmapOrDie(void *addr, uptr size);
+// Behaves just like MmapOrDie, but tolerates out of memory condition, in that
+// case returns nullptr.
+void *MmapOrDieOnFatalError(uptr size, const char *mem_type);
 void *MmapFixedNoReserve(uptr fixed_addr, uptr size,
                          const char *name = nullptr);
 void *MmapNoReserveOrDie(uptr size, const char *mem_type);
Index: lib/sanitizer_common/sanitizer_allocator_secondary.h
===================================================================
--- lib/sanitizer_common/sanitizer_allocator_secondary.h
+++ lib/sanitizer_common/sanitizer_allocator_secondary.h
@@ -36,9 +36,12 @@
     if (alignment > page_size_)
       map_size += alignment;
     // Overflow.
-    if (map_size < size) return ReturnNullOrDieOnBadRequest();
+    if (map_size < size)
+      return ReturnNullOrDieOnBadRequest();
     uptr map_beg = reinterpret_cast<uptr>(
-        MmapOrDie(map_size, "LargeMmapAllocator"));
+        MmapOrDieOnFatalError(map_size, "LargeMmapAllocator"));
+    if (!map_beg)
+      return ReturnNullOrDieOnOOM();
     CHECK(IsAligned(map_beg, page_size_));
     MapUnmapCallback().OnMap(map_beg, map_size);
     uptr map_end = map_beg + map_size;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D34243.102681.patch
Type: text/x-patch
Size: 3386 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20170615/e32c65f1/attachment.bin>