Commit Graph

55 Commits

Author SHA1 Message Date
Dmitry Vyukov 765921de5b sanitizer_common: prefix thread-safety macros with SANITIZER_
Currently we use very common names for macros like ACQUIRE/RELEASE,
which cause conflicts with system headers.
Prefix all macros with SANITIZER_ to avoid conflicts.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D116652
2022-01-07 15:11:00 +01:00
Vitaly Buka be60b6aac5 [NFC][sanitizer] Make const PointerIsMine and FromPrimary 2021-11-10 15:22:29 -08:00
Vitaly Buka 9939e562f7 [NFC][sanitizer] Refactor Maps into templates
Depends on D111599.

Reviewed By: dvyukov

Differential Revision: https://reviews.llvm.org/D111605
2021-10-12 13:37:44 -07:00
Vitaly Buka 9ccb6024a0 [NFC][sanitizer] Add a few consts 2021-10-10 22:59:43 -07:00
Dmitry Vyukov 10158b52dc sanitizer_common: fix 32-bit build
https://reviews.llvm.org/D105716 enabled thread safety annotations,
and that broke 32-bit build:
https://green.lab.llvm.org/green/job/lldb-cmake/33604/consoleFull#-77815080549ba4694-19c4-4d7e-bec5-911270d8a58c

1. Enable thread-safety analysis in unit tests
(this catches the breakage even in 64-bit mode).
2. Add NO_THREAD_SAFETY_ANALYSIS to sanitizer_allocator_primary32.h
to unbreak the build.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D105808
2021-07-12 14:03:13 +02:00
Matt Morehouse 642b80013c [sanitizer] Support dynamic premapped R/W range in primary allocator.
The main use case for this change is HWASan aliasing mode, which premaps
the alias space adjacent to the dynamic shadow.  With this change, the
primary allocator can allocate from the alias space instead of a
separate region.

Reviewed By: vitalybuka, eugenis

Differential Revision: https://reviews.llvm.org/D98293
2021-03-23 10:00:14 -07:00
Vitaly Buka 1e9c90921f Revert "[sanitizer] Support dynamic premapped R/W range in primary allocator."
Fails on Windows https://lab.llvm.org/buildbot/#/builders/127/builds/7999
and Android https://lab.llvm.org/buildbot/#/builders/77/builds/4839

This reverts commit bca0cf768b.
2021-03-22 18:52:56 -07:00
Matt Morehouse bca0cf768b [sanitizer] Support dynamic premapped R/W range in primary allocator.
The main use case for this change is HWASan aliasing mode, which premaps
the alias space adjacent to the dynamic shadow.  With this change, the
primary allocator can allocate from the alias space instead of a
separate region.

Reviewed By: vitalybuka, eugenis

Differential Revision: https://reviews.llvm.org/D98293
2021-03-22 14:44:52 -07:00
Vitaly Buka 27650a5fed [NFC][Asan] Remove Debug code
Used for https://github.com/google/sanitizers/issues/1193

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86933
2020-09-08 13:59:59 -07:00
Vitaly Buka 2b71b7f791 [NFC][Asan] Set AP32::kMetadataSize to 0
Asan does not use metadata with primary allocators.
It should match AP64::kMetadataSize whic is 0.

Depends on D86917.

Reviewed By: morehouse

Differential Revision: https://reviews.llvm.org/D86919
2020-09-03 14:23:51 -07:00
Kostya Serebryany 58743040ff Add more debug code for https://github.com/google/sanitizers/issues/1193 (getting desperate, not being able to reproduce it for a few months, but the users are seeing it)
mode debug code

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D84819
2020-07-29 11:13:11 -07:00
Vitaly Buka 93a3cbc746 Revert r369472 and r369441
check-sanitizer does not work on Linux

llvm-svn: 369495
2019-08-21 05:06:21 +00:00
Sebastian Pop 63487bfec9 [AArch64] Speed-up leak and address sanitizers on AArch64 for 48-bit VMA
This patch fixes https://github.com/google/sanitizers/issues/703
On a Graviton-A1 aarch64 machine with 48-bit VMA,
the time spent in LSan and ASan reduced from 2.5s to 0.01s when running

clang -fsanitize=leak compiler-rt/test/lsan/TestCases/sanity_check_pure_c.c && time ./a.out
clang -fsanitize=address compiler-rt/test/lsan/TestCases/sanity_check_pure_c.c && time ./a.out

With this patch, LSan and ASan create both the 32 and 64 allocators and select
at run time between the two allocators following a global variable that is
initialized at init time to whether the allocator64 can be used in the virtual
address space.

Differential Revision: https://reviews.llvm.org/D60243

llvm-svn: 369441
2019-08-20 20:54:05 +00:00
Vitaly Buka 59bcb788ec [sanitizer][NFC] Add const/static into a couple of methods
llvm-svn: 359728
2019-05-01 21:22:59 +00:00
Vitaly Buka 0f21545a3c [sanitizer] Calculate SizeClassAllocator32::ByteMap type from Params::kSpaceSize and Params::kRegionSizeLog
Reviewers: eugenis

Subscribers: kubamracek, cryptoad, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D61206

llvm-svn: 359374
2019-04-27 06:30:52 +00:00
Vitaly Buka 83c6d10b62 [sanitizer] NFC: add static_assert to confirm that we use reasonable ByteMap type
Summary: If bots work we can replace #ifs with template specialization by TwoLevelByteMapSize1.

There is known users of TwoLevelByteMap with TwoLevelByteMapSize1 equal 8,
and users of FlatByteMap with TwoLevelByteMapSize1 equal 2.

Reviewers: eugenis

Subscribers: kubamracek, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D61200

llvm-svn: 359364
2019-04-27 02:13:26 +00:00
JF Bastien 8504b5f64f Revert "[sanitizer] NFC: add static_assert to confirm that we use optimal ByteMap type"
Fails on bots with:

/Users/buildslave/jenkins/workspace/clang-stage1-cmake-RA-expensive/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h:69:3: error: static_assert failed due to requirement 'TwoLevelByteMapSize1 > 128' "TwoLevelByteMap should be used"
  static_assert(TwoLevelByteMapSize1 > 128, "TwoLevelByteMap should be used");
  ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~
/Users/buildslave/jenkins/workspace/clang-stage1-cmake-RA-expensive/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h:29:34: note: in instantiation of template class '__sanitizer::SizeClassAllocator32<__sanitizer::AP32>' requested here
                        typename PrimaryAllocator::AddressSpaceView>::value,
                                 ^

http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-expensive/13960/console

llvm-svn: 359352
2019-04-26 22:29:49 +00:00
Vitaly Buka 85dcdae5e3 [sanitizer] NFC: add static_assert to confirm that we use optimal ByteMap type
Summary: If bots work we can replace #ifs with template specialization by TwoLevelByteMapSize1.

Reviewers: eugenis

Subscribers: kubamracek, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D61200

llvm-svn: 359333
2019-04-26 18:22:47 +00:00
Vitaly Buka 1a607ff043 [lsan] Use SANITIZER_WORDSIZE when selecting ByteMap
Originally this code was added for 64-bit platform and it was never update.
Add static_assert to validate type of ByteMap.

llvm-svn: 359286
2019-04-26 08:24:38 +00:00
Vitaly Buka d8e9c3a999 Revert "[lsan] Use SANITIZER_WORDSIZE when selecting ByteMap"
New static_assert fails on a bot.

This reverts commit r359269.

llvm-svn: 359276
2019-04-26 05:19:32 +00:00
Vitaly Buka 3db2a7a04f [lsan] Use SANITIZER_WORDSIZE when selecting ByteMap
Originally this code as added for 64-bit platform and was never changed.
Add static_assert to make sure that we have correct map on all platforms.

llvm-svn: 359269
2019-04-26 04:20:27 +00:00
Vitaly Buka d3ed66dfb3 SanitizerCommon: 64-bit SPARC/Linux port
Summary:
This patch contains the bits required to make the common 32-bit allocator work on SPARC64/Linux.

Patch by Eric Botcazou.

Reviewers: #sanitizers, vitalybuka

Reviewed By: #sanitizers, vitalybuka

Subscribers: krytarowski, vitalybuka, ro, jyknight, kubamracek, fedor.sergeev, jdoerfert, llvm-commits, #sanitizers

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58432

llvm-svn: 355978
2019-03-12 21:02:04 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Dan Liew 09f6d77840 Fix `static_assert()` scope in `SizeClassAllocator32`.
It should be at the class scope and not inside the `Init(...)` function
because we want to error out as soon as the wrong type is constructed.
At the function scope the `static_assert` is only checked if the
function might be called.

This is a follow up to r349138.

rdar://problem/45284065

llvm-svn: 349959
2018-12-21 21:41:31 +00:00
Dan Liew 41fec1bfc5 Introduce `AddressSpaceView` template parameter to `SizeClassAllocator32`, `FlatByteMap`, and `TwoLevelByteMap`.
Summary:
This is a follow up patch to r346956 for the `SizeClassAllocator32`
allocator.

This patch makes `AddressSpaceView` a template parameter both to the
`ByteMap` implementations (but makes `LocalAddressSpaceView` the
default), some `AP32` implementations and is used in `SizeClassAllocator32`.
The actual changes to `ByteMap` implementations and
`SizeClassAllocator32` are very simple. However the patch is large
because it requires changing all the `AP32` definitions, and users of
those definitions.

For ASan and LSan we make `AP32` and `ByteMap` templateds type that take
a single `AddressSpaceView` argument. This has been done because we will
instantiate the allocator with a type that isn't `LocalAddressSpaceView`
in the future patches. For the allocators used in the other sanitizers
(i.e. HWAsan, MSan, Scudo, and TSan) use of `LocalAddressSpaceView` is
hard coded because we do not intend to instantiate the allocators with
any other type.

In the cases where untemplated types have become templated on a single
`AddressSpaceView` parameter (e.g. `PrimaryAllocator`) their name has
been changed to have a `ASVT` suffix (Address Space View Type) to
indicate they are templated.  The only exception to this are the `AP32`
types due to the desire to keep the type name as short as possible.

In order to check that template is instantiated in the correct a way a
`static_assert(...)` has been added that checks that the
`AddressSpaceView` type used by `Params::ByteMap::AddressSpaceView` matches
the `Params::AddressSpaceView`. This uses the new `sanitizer_type_traits.h`
header.

rdar://problem/45284065

Reviewers: kcc, dvyukov, vitalybuka, cryptoad, eugenis, kubamracek, george.karpenkov

Subscribers: mgorny, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D54904

llvm-svn: 349138
2018-12-14 09:03:18 +00:00
Kostya Kortchinsky 561228b2fa [sanitizer] Minor 32-bit primary improvements
Summary:
For the 32-bit TransferBatch:
- `SetFromArray` callers have bounds `count`, so relax the `CHECK` to `DCHECK`;
- same for `Add`;
- mark `CopyToArray` as `const`;
For the 32-bit Primary:
- `{Dea,A}llocateBatch` are only called from places that check `class_id`,
  relax the `CHECK` to `DCHECK`;
- same for `AllocateRegion`;
- remove `GetRegionBeginBySizeClass` that is not used;
- use a local variable for the random shuffle state, so that the compiler can
  use a register instead of reading and writing to the `SizeClassInfo` at every
  iteration;
For the 32-bit local cache:
- pass the count to drain instead of doing a `Min` everytime which is at times
  superfluous.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D46657

llvm-svn: 332478
2018-05-16 15:13:26 +00:00
Kostya Kortchinsky 440d76c559 [sanitizer] s/TestOnlyInit/Init for the allocator ByteMap (NFC)
Summary:
The `TestOnlyInit` function of `{Flat,TwoLevel}ByteMap` seems to be a misnomer
since the function is used outside of tests as well, namely in
`SizeClassAllocator32::Init`. Rename it to `Init` and update the callers.

Reviewers: alekseyshl, vitalybuka

Reviewed By: vitalybuka

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D46408

llvm-svn: 331662
2018-05-07 19:02:19 +00:00
Kostya Kortchinsky 3a9245481f [sanitizer] Remove unused 32-bit allocator TransferBatch parameter
Summary:
NFC. Remove an unused parameter in
`SizeClassAllocator32::TransferBatch::SetFromArray`, and thus get rid of the
compilation warning.

Reviewers: alekseyshl, vitalybuka

Reviewed By: vitalybuka

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D46397

llvm-svn: 331477
2018-05-03 19:14:07 +00:00
Kostya Kortchinsky 4563b78b99 [sanitizer] Allow for the allocator "names" to be set by the tools
Summary:
In the same spirit of SanitizerToolName, allow the Primary & Secondary
allocators to have names that can be set by the tools via PrimaryAllocatorName
and SecondaryAllocatorName.

Additionally, set a non-default name for Scudo.

Reviewers: alekseyshl, vitalybuka

Reviewed By: alekseyshl, vitalybuka

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D45600

llvm-svn: 330055
2018-04-13 19:21:27 +00:00
Kostya Kortchinsky 85ecac5f3f [sanitizer] Align & pad the allocator structures to the cacheline size v2
Summary:
This is a new version of D44261, which broke some builds with older gcc, as
they can't align on a constexpr, but rather require an integer (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56859) among others.

We introduce `SANITIZER_CACHE_LINE_SIZE` in `sanitizer_platform.h` to be
used in `ALIGNED` attributes instead of using directly `kCacheLineSize`.

Reviewers: alekseyshl, thakis

Reviewed By: alekseyshl

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44326

llvm-svn: 327297
2018-03-12 17:18:26 +00:00
Kostya Kortchinsky 112d7a435b [sanitizer] Revert rCRT327145
Summary:
It breaks the Chromium toolchain due to:
```
lib/sanitizer_common/sanitizer_allocator_primary32.h:269:34: error: requested alignment is not an integer constant
   struct ALIGNED(kCacheLineSize) SizeClassInfo {
```

Reviewers: alekseyshl, thakis

Reviewed By: thakis

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44320

llvm-svn: 327167
2018-03-09 20:17:12 +00:00
Kostya Kortchinsky 69df838b52 [sanitizer] Align & pad the allocator structures to the cacheline size
Summary:
Both `SizeClassInfo` structures for the 32-bit primary & `RegionInfo`
structures for the 64-bit primary can be used by different threads, and as such
they should be aligned & padded to the cacheline size to avoid false sharing.
The former was padded but the array was not aligned, the latter was not padded
but we lucked up as the size of the structure was 192 bytes, and aligned by
the properties of `mmap`.

I plan on adding a couple of fields to the `RegionInfo`, and some highly
threaded tests pointed out that without proper padding & alignment, performance
was getting a hit - and it is going away with proper padding.

This patch makes sure that we are properly padded & aligned for both. I used
a template to avoid padding if the size is already a multiple of the cacheline
size. There might be a better way to do this, I am open to suggestions.

Reviewers: alekseyshl, dvyukov

Reviewed By: alekseyshl

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44261

llvm-svn: 327145
2018-03-09 16:18:38 +00:00
Kostya Kortchinsky 1022220b16 [sanitizer] Size class map & local cache improvements
Summary:
- Reland rL324263, this time allowing for a compile-time decision as to whether
  or not use the 32-bit division. A single test is using a class map covering
  a maximum size greater than 4GB, this can be checked via the template
  parameters, and allows SizeClassAllocator64PopulateFreeListOOM to pass;
- `MaxCachedHint` is always called on a class id for which we have already
  computed the size, but we still recompute `Size(class_id)`. Change the
  prototype of the function to work on sizes instead of class ids. This also
  allows us to get rid of the `kBatchClassID` special case. Update the callers
  accordingly;
- `InitCache` and `Drain` will start iterating at index 1: index 0 contents are
  unused and can safely be left to be 0. Plus we do not pay the cost of going
  through an `UNLIKELY` in `MaxCachedHint`, and touching memory that is
  otherwise not used;
- `const` some variables in the areas modified;
- Remove an spurious extra line at the end of a file.

Reviewers: alekseyshl, tl0gic, dberris

Reviewed By: alekseyshl, dberris

Subscribers: dberris, kubamracek, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D43088

llvm-svn: 324906
2018-02-12 16:59:17 +00:00
Kostya Kortchinsky c484912b06 [sanitizer] Random shuffling of chunks for the 32-bit Primary Allocator
Summary:
The 64-bit primary has had random shuffling of chunks for a while, this
implements it for the 32-bit primary. Scudo is currently the only user of
`kRandomShuffleChunks`.

This change consists of a few modifications:
- move the random shuffling functions out of the 64-bit primary to
  `sanitizer_common.h`. Alternatively I could move them to
  `sanitizer_allocator.h` as they are only used in the allocator, I don't feel
  strongly either way;
- small change in the 64-bit primary to make the `rand_state` initialization
  `UNLIKELY`;
- addition of a `rand_state` in the 32-bit primary's `SizeClassInfo` and
  shuffling of chunks when populating the free list.
- enabling the `random_shuffle.cpp` test on platforms using the 32-bit primary
  for Scudo.

Some comments on why the shuffling is done that way. Initially I just
implemented a `Shuffle` function in the `TransferBatch` which was simpler but I
came to realize this wasn't good enough: for chunks of 10000 bytes for example,
with a `CompactSizeClassMap`, a batch holds only 1 chunk, meaning shuffling the
batch has no effect, while a region is usually 1MB, eg: 104 chunks of that size.
So I decided to "stage" the newly gathered chunks in a temporary array that
would be shuffled prior to placing the chunks in batches.
The result is looping twice through n_chunks even if shuffling is not enabled,
but I didn't notice any significant significant performance impact.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D39244

llvm-svn: 316596
2017-10-25 17:24:56 +00:00
Alex Shlyapnikov 028c4cddad [Sanitizers] New sanitizer API to purge allocator quarantine.
Summary:
Purging allocator quarantine and returning memory to OS might be desired
between fuzzer iterations since, most likely, the quarantine is not
going to catch bugs in the code under fuzz, but reducing RSS might
significantly prolong the fuzzing session.

Reviewers: cryptoad

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D39153

llvm-svn: 316347
2017-10-23 17:12:07 +00:00
Kostya Kortchinsky 476f21d87e [sanitizer] Re-introduce kUseSeparateSizeClassForBatch for the 32-bit Primary
Summary:
Currently `TransferBatch` are located within the same memory regions as
"regular" chunks. This is not ideal for security: they make for an interesting
target to overwrite, and are not protected by the frontend (namely, Scudo).

To solve this, we re-introduce `kUseSeparateSizeClassForBatch` for the 32-bit
Primary allowing for `TransferBatch` to end up in their own memory region.
Currently only Scudo would use this new feature, the default behavior remains
unchanged. The separate `kBatchClassID` was used for a brief period of time
previously but removed when the 64-bit ended up using the "free array".

Reviewers: alekseyshl, kcc, eugenis

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D37082

llvm-svn: 311891
2017-08-28 15:20:02 +00:00
Kostya Kortchinsky b138ab810f [sanitizer] Small tweaks and fixes to allocator related functions
Summary:
In `sanitizer_allocator_primary32.h`:
- rounding up in `MapWithCallback` is not needed as `MmapOrDie` does it. Note
  that the 64-bit counterpart doesn't round up, this keeps the behavior
  consistent;
- since `IsAligned` exists, use it in `AllocateRegion`;
- in `PopulateFreeList`:
  - checking `b->Count` to be greater than 0 when `b->Count() == max_count` is
    redundant when done more than once. Just check that `max_count` is greater
    than 0 out of the loop; the compiler (at least on ARM) didn't optimize it;
  - mark the batch creation failure as `UNLIKELY`;

In `sanitizer_allocator_primary64.h`:
- in `MapWithCallback`, mark the failure condition as `UNLIKELY`;

In `sanitizer_posix.h`:
- mark a bunch of Mmap related failure conditions as `UNLIKELY`;
- in `MmapAlignedOrDieOnFatalError`, we have `IsAligned`, so use it; rearrange
  the conditions as one test was redudant;
- in `MmapFixedImpl`, 30 chars was not large enough to hold the message and a
  full 64-bit address (or at least a 48-bit usermode address), increase to 40.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: aemerson, kubamracek, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D34840

llvm-svn: 306834
2017-06-30 16:05:40 +00:00
Alex Shlyapnikov f3cc7cc3d8 [Sanitizers] 32 bit allocator respects allocator_may_return_null flag
Summary:
Make SizeClassAllocator32 return nullptr when it encounters OOM, which
allows the entire sanitizer's allocator to follow allocator_may_return_null=1
policy, even for small allocations (LargeMmapAllocator is already fixed
by D34243).

Will add a test for OOM in primary allocator later, when
SizeClassAllocator64 can gracefully handle OOM too.

Reviewers: eugenis

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D34433

llvm-svn: 305972
2017-06-22 00:02:37 +00:00
Kostya Kortchinsky 77f30c9c31 [sanitizer] Reverting D34152
Summary:
This broke thread_local_quarantine_pthread_join.cc on some architectures, due
to the overhead of the stashed regions. Reverting while figuring out the best
way to deal with it.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D34213

llvm-svn: 305404
2017-06-14 17:32:26 +00:00
Kostya Kortchinsky eca926ab3a [sanitizer] MmapAlignedOrDie changes to reduce fragmentation
Summary:
The reasoning behind this change is explained in D33454, which unfortunately
broke the Windows version (due to the platform not supporting partial unmapping
of a memory region).

This new approach changes `MmapAlignedOrDie` to allow for the specification of
a `padding_chunk`. If non-null, and the initial allocation is aligned, this
padding chunk will hold the address of the extra memory (of `alignment` bytes).
This allows `AllocateRegion` to get 2 regions if the memory is aligned
properly, and thus help reduce fragmentation (and saves on unmapping
operations). As with the initial D33454, we use a stash in the 32-bit Primary
to hold those extra regions and return them on the fast-path.

The Windows version of `MmapAlignedOrDie` will always return a 0
`padding_chunk` if one was requested.

Reviewers: alekseyshl, dvyukov, kcc

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D34152

llvm-svn: 305391
2017-06-14 15:32:17 +00:00
Kostya Kortchinsky 5d0ecbc8d9 [sanitizer] Revert rL303879 as it breaks Windows
Summary:
Apparently Windows's `UnmapOrDie` doesn't support partial unmapping. Which
makes the new region allocation technique not Windows compliant.

Reviewers: alekseyshl, dvyukov

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D33554

llvm-svn: 303883
2017-05-25 16:54:44 +00:00
Kostya Kortchinsky 0dd40cf28d [sanitizer] Change the 32-bit Primary AllocateRegion to reduce fragmentation
Summary:
Currently, AllocateRegion has a tendency to fragment memory: it allocates
`2*kRegionSize`, and if the memory is aligned, will unmap `kRegionSize` bytes,
thus creating a hole, which can't itself be reused for another region. This
is exacerbated by the fact that if 2 regions get allocated one after another
without any `mmap` in between, the second will be aligned due to mappings 
generally being contiguous.

An idea, suggested by @alekseyshl, to prevent such a behavior is to have a
stash of regions: if the `2*kRegionSize` allocation is properly aligned, split
it in two, and stash the second part to be returned next time a region is
requested.

At this point, I thought about a couple of ways to implement this:
 - either an `IntrusiveList` of regions candidates, storing `next` at the
   begining of the region;
 - a small array of regions candidates existing in the Primary.

While the second option is more constrained in terms of size, it offers several
advantages:
 - security wise, a pointer in a region candidate could be overflowed into, and
   abused when popping an element;
 - we do not dirty the first page of the region by storing something in it;
 - unless several threads request regions simultaneously from different size
   classes, the stash rarely goes above 1 entry.

I am not certain about the Windows impact of this change, as `sanitizer_win.cc`
has its own version of MmapAlignedOrDie, maybe someone could chime in on this.

MmapAlignedOrDie is effectively unused after this change and could be removed
at a later point. I didn't notice any sizeable performance gain, even though we
are saving a few `mmap`/`munmap` syscalls.

Reviewers: alekseyshl, kcc, dvyukov

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D33454

llvm-svn: 303879
2017-05-25 16:19:57 +00:00
Kostya Kortchinsky dc646a0889 [sanitizer] Change SizeClassAllocator32 to accept just one template
Summary:
With rL279771, SizeClassAllocator64 was changed to accept only one template
instead of 5, for the following reasons: "First, this will make the mangled
names shorter. Second, this will make adding more parameters simpler". This
patch mirrors that work for SizeClassAllocator32.

This is in preparation for introducing the randomization of chunks in the
32-bit SizeClassAllocator in a later patch.

Reviewers: kcc, alekseyshl, dvyukov

Reviewed By: alekseyshl

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D33141

llvm-svn: 303071
2017-05-15 14:47:19 +00:00
Evgeniy Stepanov d3305afc75 Return memory to OS right after free (not in the async thread).
Summary:
In order to avoid starting a separate thread to return unused memory to
the system (the thread interferes with process startup on Android,
Zygota waits for all threads to exit before fork, but this thread never
exits), try to return it right after free.

Reviewers: eugenis

Subscribers: cryptoad, filcab, danalbert, kubabrecka, llvm-commits

Patch by Aleksey Shlyapnikov.

Differential Revision: https://reviews.llvm.org/D27003

llvm-svn: 288091
2016-11-29 00:22:50 +00:00
Kostya Serebryany 4fd30769c1 [sanitizer] remove kBatchClassID that is not used any more; NFC
llvm-svn: 280185
2016-08-31 00:37:33 +00:00
Kostya Serebryany b72479b84a [asan] first attempt at releasing free-d memory back to the system using madvise. Requires quite some tuning.
llvm-svn: 279887
2016-08-26 23:58:42 +00:00
Kostya Serebryany ce2163459f [sanitizer] allocator: split the local cache class into two, one for 32-bit allocator and one for 64-bit one. NFC. The two imlementations will diverge in the following changes.
llvm-svn: 279495
2016-08-23 00:30:43 +00:00
Kostya Serebryany 1ab649649d [sanitizer] use 32-bit offset instead of 64-bit pointers in the 64-bit allocator's transfer batches. This saves 2x memory for the transfer batches (up to ~1.5% overall in some cases)
llvm-svn: 278179
2016-08-09 23:30:22 +00:00
Kostya Serebryany d4a5749677 [sanitizer] minor refactoring in the allocator, NFC
llvm-svn: 278163
2016-08-09 20:54:50 +00:00
Kostya Serebryany 4cd2845e6a [sanitizer] allocator: move TransferBatch into SizeClassAllocator64/SizeClassAllocator32 because we actually need different iplementations for the 64- and 32-bit case. NFC; the following patches will make the TransferBatch implementations differ
llvm-svn: 277899
2016-08-06 01:24:11 +00:00