MSan divides the virtual address space into APP, INVALID, SHADOW and
ORIGIN memory. The allocator usually just steals a bit of the APP
address space: typically the bottom portion of the PIE binaries section,
which works because the Linux kernel maps from the top of the PIE
binaries section. However, if ASLR is very aggressive, the binary may
end up mapped in the same location where the allocator wants to live;
this results in a segfault.
This patch adds in a MappingDesc::ALLOCATOR type and enforces that the
memory range for the allocator is not occupied by anything else.
Since the allocator range information is not readily available in
msan.h, we duplicate the information from msan_allocator.cpp.
Note: aggressive ASLR can also lead to a different type of failure,
where the PIE binaries/libraries are mapped entirely outside of the
APP/ALLOCATOR sections; that will be addressed in a separate patch
(https://github.com/llvm/llvm-project/pull/85142).
This patch adds basic memory sanitizer support for loongarch64
with 47-bit VMA, which memory layout is based on x86_64.
The LLVM part of the LoongArch memory sanitizer implementation will
be done separately, which will fix failing tests in check-msan.
These failing tests fail with the following same error: "error in
backend: unsupported architecture".
Reviewed By: #sanitizers, vitalybuka, MaskRay
Differential Revision: https://reviews.llvm.org/D140528
The primary motivation for this change is to allow FreeHooks to obtain
the allocated size of the pointer being freed in a fast, efficient manner.
Differential Revision: https://reviews.llvm.org/D151360
__sanitizer_get_current_allocated_bytes had as body, but allocator
caches were not registered to collect stats. It's done by
SizeClassAllocator64LocalCache::Init().
Reviewed By: kstoimenov
Differential Revision: https://reviews.llvm.org/D151352
D147005 introduced __sanitizer_get_allocated_begin, with a return
value of void*. This involved a few naughty casts that dropped the
const. This patch adds back the const qualifier.
Differential Revision: https://reviews.llvm.org/D147489
Now that D137666 requires 48-bit VMA for AArch64, we can switch to
SizeClassAllocator64 for a slightly more efficient allocator
(asan/lsan already switched by default).
It seems that we can pick kSpaceBeg = 0xE00000000000ULL to support both Linux
("app-15") and FreeBSD ("high memory").
Reviewed By: #sanitizers, vitalybuka
Differential Revision: https://reviews.llvm.org/D140792
r249754 (2015) added this macro (not set anywhere) for an escape hatch.
This old layout has been non-working for many years (Linux
arch/x86/include/asm/elf.h ELF_ET_DYN_BASE is outside the APP range):
FATAL: Code 0x558547327980 is out of application range. Non-PIE build?
FATAL: MemorySanitizer can not mmap the shadow memory.
FATAL: Make sure to compile with -fPIE and to link with -pie.
FATAL: Disabling ASLR is known to cause this error.
FATAL: If running under GDB, try 'set disable-randomization off'.
Non-pie doesn't work either.
Usually when we generated stacktraces the process is in error state, so
running hooks may crash the process and prevent meaningfull error report.
Symbolizer, unwinder and pthread are potential source of mallocs.
https://b.corp.google.com/issues/228110771
Reviewed By: kda
Differential Revision: https://reviews.llvm.org/D123566
Usually when we generated stacktraces the process is in error state, so
running hooks may crash the process and prevent meaningfull error report.
Symbolizer, unwinder and pthread are potential source of mallocs.
https://b.corp.google.com/issues/228110771
Reviewed By: kda
Differential Revision: https://reviews.llvm.org/D123566
This is to help review refactor the allocator code.
So it is easy to see which are the real public interfaces.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D101586
Summary:
The flag allows the user to specify a maximum allocation size that the
sanitizers will honor. Any larger allocations will return nullptr or
crash depending on allocator_may_return_null.
Reviewers: kcc, eugenis
Reviewed By: kcc, eugenis
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D69576
