diff options
author | Kuba Mracek <mracek@apple.com> | 2017-07-12 23:29:21 +0000 |
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committer | Kuba Mracek <mracek@apple.com> | 2017-07-12 23:29:21 +0000 |
commit | b40ba7db5e71b65a5c6a12d997403bf8fbac35f3 (patch) | |
tree | 8609b70a6931a307125d9575c14ee4ce873bcc77 /lib/sanitizer_common/sanitizer_mac_libcdep.cc | |
parent | 1832be2ba37b2ca197edf7239eead2f5b43ed838 (diff) |
[asan] For iOS/AArch64, if the dynamic shadow doesn't fit, restrict the VM space
On iOS/AArch64, the address space is very limited and has a dynamic maximum address based on the configuration of the device. We're already using a dynamic shadow, and we find a large-enough "gap" in the VM where we place the shadow memory. In some cases and some device configuration, we might not be able to find a large-enough gap: E.g. if the main executable is linked against a large number of libraries that are not part of the system, these libraries can fragment the address space, and this happens before ASan starts initializing.
This patch has a solution, where we have a "backup plan" when we cannot find a large-enough gap: We will restrict the address space (via MmapFixedNoAccess) to a limit, for which the shadow limit will fit.
Differential Revision: https://reviews.llvm.org/D35098
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@307865 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_mac_libcdep.cc')
-rw-r--r-- | lib/sanitizer_common/sanitizer_mac_libcdep.cc | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/sanitizer_common/sanitizer_mac_libcdep.cc b/lib/sanitizer_common/sanitizer_mac_libcdep.cc new file mode 100644 index 000000000..c95daa937 --- /dev/null +++ b/lib/sanitizer_common/sanitizer_mac_libcdep.cc @@ -0,0 +1,30 @@ +//===-- sanitizer_mac_libcdep.cc ------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is shared between various sanitizers' runtime libraries and +// implements OSX-specific functions. +//===----------------------------------------------------------------------===// + +#include "sanitizer_platform.h" +#if SANITIZER_MAC +#include "sanitizer_mac.h" + +#include <sys/mman.h> + +namespace __sanitizer { + +void RestrictMemoryToMaxAddress(uptr max_address) { + uptr size_to_mmap = GetMaxVirtualAddress() + 1 - max_address; + void *res = MmapFixedNoAccess(max_address, size_to_mmap, "high gap"); + CHECK(res != MAP_FAILED); +} + +} // namespace __sanitizer + +#endif // SANITIZER_MAC |