forked from OSchip/llvm-project
db00fac2a2
This CL allows asan allocator in fuchsia to decommit shadow memory for memory allocated using mmap. Big allocations in asan end up being allocated via `mmap` and freed with `munmap`. However, when that memory is freed, asan returns the corresponding shadow memory back to the OS via a call to `ReleaseMemoryPagesToOs`. In fuchsia, `ReleaseMemoryPagesToOs` is a no-op: to be able to free memory back to the OS, you have to hold a handle to the vmo you want to modify, which is tricky at the ReleaseMemoryPagesToOs level as that function is not exclusively used for shadow memory. The function `__sanitizer_fill_shadow` fills a given shadow memory range with a specific value, and if that value is 0 (unpoison) and the memory range is bigger than a threshold parameter, it will decommit that memory if it is all zeroes. This CL modifies the `FlushUnneededASanShadowMemory` function in `asan_poisoning.cpp` to add a call to `__sanitizer_fill_shadow` with value and threshold = 0. This way, all the unneeded shadow memory gets returned back to the OS. A test for this behavior can be found in fxrev.dev/391974 Differential Revision: https://reviews.llvm.org/D80355 Change-Id: Id6dd85693e78a222f0329d5b2201e0da753e01c0 |
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|---|---|---|
| .. | ||
| scripts | ||
| tests | ||
| .clang-format | ||
| CMakeLists.txt | ||
| README.txt | ||
| asan.syms.extra | ||
| asan_activation.cpp | ||
| asan_activation.h | ||
| asan_activation_flags.inc | ||
| asan_allocator.cpp | ||
| asan_allocator.h | ||
| asan_blacklist.txt | ||
| asan_debugging.cpp | ||
| asan_descriptions.cpp | ||
| asan_descriptions.h | ||
| asan_errors.cpp | ||
| asan_errors.h | ||
| asan_fake_stack.cpp | ||
| asan_fake_stack.h | ||
| asan_flags.cpp | ||
| asan_flags.h | ||
| asan_flags.inc | ||
| asan_fuchsia.cpp | ||
| asan_globals.cpp | ||
| asan_globals_win.cpp | ||
| asan_init_version.h | ||
| asan_interceptors.cpp | ||
| asan_interceptors.h | ||
| asan_interceptors_memintrinsics.cpp | ||
| asan_interceptors_memintrinsics.h | ||
| asan_interceptors_vfork.S | ||
| asan_interface.inc | ||
| asan_interface_internal.h | ||
| asan_internal.h | ||
| asan_linux.cpp | ||
| asan_lock.h | ||
| asan_mac.cpp | ||
| asan_malloc_linux.cpp | ||
| asan_malloc_local.h | ||
| asan_malloc_mac.cpp | ||
| asan_malloc_win.cpp | ||
| asan_mapping.h | ||
| asan_mapping_myriad.h | ||
| asan_mapping_sparc64.h | ||
| asan_memory_profile.cpp | ||
| asan_new_delete.cpp | ||
| asan_poisoning.cpp | ||
| asan_poisoning.h | ||
| asan_posix.cpp | ||
| asan_preinit.cpp | ||
| asan_premap_shadow.cpp | ||
| asan_premap_shadow.h | ||
| asan_report.cpp | ||
| asan_report.h | ||
| asan_rtems.cpp | ||
| asan_rtl.cpp | ||
| asan_scariness_score.h | ||
| asan_shadow_setup.cpp | ||
| asan_stack.cpp | ||
| asan_stack.h | ||
| asan_stats.cpp | ||
| asan_stats.h | ||
| asan_suppressions.cpp | ||
| asan_suppressions.h | ||
| asan_thread.cpp | ||
| asan_thread.h | ||
| asan_win.cpp | ||
| asan_win_dll_thunk.cpp | ||
| asan_win_dynamic_runtime_thunk.cpp | ||
| asan_win_weak_interception.cpp | ||
| weak_symbols.txt | ||
README.txt
AddressSanitizer RT
================================
This directory contains sources of the AddressSanitizer (ASan) runtime library.
Directory structure:
README.txt : This file.
Makefile.mk : File for make-based build.
CMakeLists.txt : File for cmake-based build.
asan_*.{cc,h} : Sources of the asan runtime library.
scripts/* : Helper scripts.
tests/* : ASan unit tests.
Also ASan runtime needs the following libraries:
lib/interception/ : Machinery used to intercept function calls.
lib/sanitizer_common/ : Code shared between various sanitizers.
ASan runtime currently also embeds part of LeakSanitizer runtime for
leak detection (lib/lsan/lsan_common.{cc,h}).
ASan runtime can only be built by CMake. You can run ASan tests
from the root of your CMake build tree:
make check-asan
For more instructions see:
https://github.com/google/sanitizers/wiki/AddressSanitizerHowToBuild