[compiler-rt] r319348 - [asan] Fix macOS FindDynamicShadowStart to consider the last gap in the VM map

[Kuba Mracek via llvm-commits]

Author: kuba.brecka
Date: Wed Nov 29 11:44:52 2017
New Revision: 319348

URL: http://llvm.org/viewvc/llvm-project?rev=319348&view=rev
Log:
[asan] Fix macOS FindDynamicShadowStart to consider the last gap in the VM map

It looks FindDynamicShadowStart has a bug: When iterating over the memory map, we will not consider the very last gap in the address space. Let's fix that.

Differential Revision: https://reviews.llvm.org/D39989


Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc?rev=319348&r1=319347&r2=319348&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_mac.cc Wed Nov 29 11:44:52 2017
@@ -890,6 +890,11 @@ uptr FindAvailableMemoryRange(uptr shado
     mach_msg_type_number_t count = kRegionInfoSize;
     kr = mach_vm_region_recurse(mach_task_self(), &address, &vmsize, &depth,
                                 (vm_region_info_t)&vminfo, &count);
+    if (kr == KERN_INVALID_ADDRESS) {
+      // No more regions beyond "address", consider the gap at the end of VM.
+      address = GetMaxVirtualAddress() + 1;
+      vmsize = 0;
+    }
     if (free_begin != address) {
       // We found a free region [free_begin..address-1].
       uptr gap_start = RoundUpTo((uptr)free_begin + left_padding, alignment);