Summary:
This patch introduces stack frame compression to GWP-ASan. Each stack frame is
variable-length integer encoded as the difference between frame[i] and
frame[i - 1]. Furthermore, we use zig-zag encoding on the difference to ensure
that negative differences are also encoded into a relatively small number of
bytes.
Examples of what the compression looks like can be seen in
`gwp_asan/tests/compression.cpp`.
This compression can reduce the memory consumption cost of stack traces by
~50%.
Reviewers: vlad.tsyrklevich
Reviewed By: vlad.tsyrklevich
Subscribers: mgorny, #sanitizers, llvm-commits, eugenis, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66189
llvm-svn: 369048
Summary:
Updates the function signature and comments for backtracing (and printing
backtraces). This update brings GWP-ASan in line with future requirements for
stack frame compression, wherein the length of the trace is provided
explicitly, rather than relying on nullptr-termination.
Reviewers: vlad.tsyrklevich
Reviewed By: vlad.tsyrklevich
Subscribers: #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66099
llvm-svn: 368619
Summary:
Adds thread ID to PRNG seed for increased entropy. In particular, this allows
multiple runs in quick succession that will have different PRNG seeds, allowing
for better demos/testing.
Reviewers: kcc
Reviewed By: kcc
Subscribers: kubamracek, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D64453
llvm-svn: 366253
Summary:
Adds two flavours of generic unwinder and all the supporting cruft. If the
supporting allocator is okay with bringing in sanitizer_common, they can use
the fast frame-pointer based unwinder from sanitizer_common. Otherwise, we also
provide the backtrace() libc-based unwinder as well. Of course, the allocator
can always specify its own unwinder and unwinder-symbolizer.
The slightly changed output format is exemplified in the first comment on this
patch. It now better incorporates backtrace information, and displays
allocation details on the second line.
Reviewers: eugenis, vlad.tsyrklevich
Reviewed By: eugenis, vlad.tsyrklevich
Subscribers: srhines, kubamracek, mgorny, cryptoad, #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D63841
llvm-svn: 364941
Summary:
Add a recursivity guard for GPA::allocate(). This means that any
recursive allocations will fall back to the supporting allocator. In future
patches, we will introduce stack trace collection support. The unwinder will be
provided by the supporting allocator, and we can't guarantee they don't call
malloc() (e.g. backtrace() on posix may call dlopen(), which may call malloc().
Furthermore, this patch packs the new TLS recursivity guard into a thread local
struct, so that TLS variables should be hopefully not fall across cache lines.
Reviewers: vlad.tsyrklevich, morehouse, eugenis
Reviewed By: eugenis
Subscribers: kubamracek, #sanitizers, llvm-commits, eugenis
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D63736
llvm-svn: 364356
to try and fix android buildbot. Also make sure that the empty dummy
test contains an output file name so the android_build.py wrapper script
doesn't check fail.
llvm-svn: 362758
Summary:
See D60593 for further information.
This patch introduces the core of GWP-ASan, being the guarded pool allocator. This class contains the logic for creating and maintaining allocations in the guarded pool. Its public interface is to be utilised by supporting allocators in order to provide sampled guarded allocation behaviour.
This patch also contains basic functionality tests of the allocator as unittests. The error-catching behaviour will be tested in upcoming patches that use Scudo as an implementing allocator.
Reviewers: vlad.tsyrklevich, eugenis, jfb
Reviewed By: vlad.tsyrklevich
Subscribers: dexonsmith, kubamracek, mgorny, cryptoad, jfb, #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62872
llvm-svn: 362636
Summary:
See D60593 for further information.
This patch introduces the configuration options for GWP-ASan. In general, we expect the supporting allocator to populate the options struct, and give that to GWP-ASan during initialisation. For allocators that are okay with pulling in sanitizer_common, we also provide an optional parser that populates the gwp_asan::Options struct with values provided in the GWP_ASAN_OPTIONS environment variable.
This patch contains very little logic, and all of the testable components (i.e. the optional parser's internal logic) is tested as part of the sanitizer_common testbed.
Reviewers: vlad.tsyrklevich, morehouse, jfb
Reviewed By: morehouse
Subscribers: dexonsmith, kubamracek, mgorny, #sanitizers, llvm-commits, vitalybuka
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62698
llvm-svn: 362527
Looks like armv8 can't handle a thousand threads, which GWP-ASan
requests when running a synchronised mutex test. Limiting this to 100 to
attempt to fix the build issue.
llvm-svn: 362163
Summary:
See D60593 for further information.
This patch pulls out the mutex implementation and the required definitions file.
We implement our own mutex for GWP-ASan currently, because:
1. We must be compatible with the sum of the most restrictive elements of the supporting allocator's build system. Current targets for GWP-ASan include Scudo (on Linux and Fuchsia), and bionic (on Android).
2. Scudo specifies `-nostdlib++ -nonodefaultlibs`, meaning we can't use `std::mutex` or `mtx_t`.
3. We can't use `sanitizer_common`'s mutex, as the supporting allocators cannot afford the extra maintenance (Android, Fuchsia) and code size (Fuchsia) overheads that this would incur.
In future, we would like to implement a shared base mutex for GWP-ASan, Scudo and sanitizer_common. This will likely happen when both GWP-ASan and Scudo standalone are not in the development phase, at which point they will have stable requirements.
Reviewers: vlad.tsyrklevich, morehouse, jfb
Reviewed By: morehouse
Subscribers: dexonsmith, srhines, cfe-commits, kubamracek, mgorny, cryptoad, jfb, #sanitizers, llvm-commits, vitalybuka, eugenis
Tags: #sanitizers, #llvm, #clang
Differential Revision: https://reviews.llvm.org/D61923
llvm-svn: 362138
Summary:
Removed dependency on c++ standard library. Some supporting allocators (namely Scudo on Fuchsia, and shortly, scudo standalone) has a hard requirement of no c++stdlib.
This patch updates the build system so that we don't have any c++ stdlib dependencies. It also will conveniently fix a racy build-order bug discrepency between GWP-ASan and libc++.
Reviewers: phosek, morehouse
Reviewed By: phosek, morehouse
Subscribers: kubamracek, mgorny, cryptoad, #sanitizers, llvm-commits, beanz, smeenai, vitalybuka
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62048
llvm-svn: 360982
Summary:
See D60593 for further information.
This patch slices off the PRNG implementation and the initial build files for GWP-ASan.
Reviewers: vlad.tsyrklevich, morehouse, vitalybuka
Reviewed By: morehouse
Subscribers: srhines, kubamracek, mgorny, #sanitizers, llvm-commits, cryptoad, eugenis
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D61867
llvm-svn: 360710
Mitch Phillips