8 Commits

Author SHA1 Message Date
Kostya Kortchinsky
4bc7f3d4d6 [scudo] Enable Scudo memory hooks for Fuchsia.
Summary:
    It would be useful for Flutter apps, especially, to be able to use
    malloc hooks to debug memory leaks on Fuchsia. They're not able to do
    this right now, so it'd be a nice bonus to throw in with the Scudo
    switchover.


Reviewers: cryptoad, alekseyshl

Reviewed By: cryptoad

Differential Revision: https://reviews.llvm.org/D48618

llvm-svn: 336139
2018-07-02 19:48:01 +00:00
Kostya Kortchinsky
1ebebde8b7 [scudo] Allow for weak hooks, gated by a define
Summary:
Hooks in the allocation & deallocation paths can be a security risk (see for an
example https://scarybeastsecurity.blogspot.com/2016/11/0day-exploit-advancing-exploitation.html
which used the glibc's __free_hook to complete exploitation).

But some users have expressed a need for them, even if only for tests and
memory benchmarks. So allow for `__sanitizer_malloc_hook` &
`__sanitizer_free_hook` to be called if defined, and gate them behind a global
define `SCUDO_CAN_USE_HOOKS` defaulting to 0.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42430

llvm-svn: 323278
2018-01-23 23:07:42 +00:00
Kostya Kortchinsky
255913b3a0 [scudo] Limit by default the TSD pool to 2 on Android
Summary:
jemalloc on Android currently uses 2 arenas
(https://android.googlesource.com/platform/external/jemalloc/+/master/Android.bp#64).
Since the Android toolchain absorbs compiler-rt and compiles it as is, we have
to enforce the same limit to somehow stay competitive in terms of memory usage.

The changes could either go in:
- `scudo_platform.h` with a default for Android of 2 (this is the solution
  implemented here);
- in `CMakeLists.txt` adding -DSCUDO_SHARED_TSD_POOL_SIZE=2 for Android.
- something else?

I don't have a strong opinion on how to do it, but it has to be done upstream
anyway.

Reviewers: alekseyshl, eugenis

Reviewed By: alekseyshl, eugenis

Subscribers: srhines, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42194

llvm-svn: 322764
2018-01-17 21:54:48 +00:00
Kostya Kortchinsky
f22f5fe910 [scudo] Adding a public Scudo interface
Summary:
The first and only function to start with allows to set the soft or hard RSS
limit at runtime. Add associated tests.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: mgorny, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D41128

llvm-svn: 320611
2017-12-13 20:41:35 +00:00
Kostya Kortchinsky
cf5b4af820 [scudo] Allow for compile-time choice of the SizeClassMap
Summary:
With this change, we allow someone to chose the `SizeClassMap` they want to use
at compile time via a define.

I feel somewhat unimaginative with the name of the defines, so if someone has a
better idea, let me know. I have been alternating between those and
`SCUDO_USE_xxx_SIZECLASSMAP` which is clearer but also longer. The issue with
those is that it wouldn't be consistent with `SCUDO_TSD_EXCLUSIVE` that should
probably become `SCUDO_USE_EXCLUSIVE_TSD` maybe?

Anyway, naming is hard, and I am not sure what makes more sense!

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: llvm-commits, srhines

Differential Revision: https://reviews.llvm.org/D40521

llvm-svn: 319350
2017-11-29 19:52:09 +00:00
Kostya Kortchinsky
91b7558ca8 [scudo] Allow to specify the maximum number of TSDs at compile time
Summary:
This introduces `SCUDO_MAX_CACHES` allowing to define an upper bound to the
number of `ScudoTSD` created in the Shared TSD model (by default 32U).
This name felt clearer than `SCUDO_MAX_TSDS` which is technically what it really
is. I am opened to suggestions if that doesn't feel right.

Additionally change `getNumberOfCPUs` to return a `u32` to be more consistent.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39338

llvm-svn: 316788
2017-10-27 20:10:14 +00:00
Kostya Kortchinsky
f4c11e353a [scudo] Allow for non-Android Shared TSD platforms, part 2
Summary:
Follow up to D38826.

We introduce `pthread_{get,set}specific` versions of `{get,set}CurrentTSD` to
allow for non Android platforms to use the Shared TSD model.
We now allow `SCUDO_TSD_EXCLUSIVE` to be defined at compile time.

A couple of things:
- I know that `#if SANITIZER_ANDROID` is not ideal within a function, but in
  the end I feel it looks more compact and clean than going the .inc route; I
  am open to an alternative if anyone has one;
- `SCUDO_TSD_EXCLUSIVE=1` requires ELF TLS support (and not emutls as this uses
  malloc). I haven't found anything to enforce that, so it's currently not
  checked.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D38854

llvm-svn: 315751
2017-10-13 20:55:31 +00:00
Kostya Kortchinsky
b59abb2590 [scudo] Scudo thread specific data refactor, part 3
Summary:
Previous parts: D38139, D38183.

In this part of the refactor, we abstract the Linux vs Android TSD dissociation
in favor of a Exclusive vs Shared one, allowing for easier platform introduction
and configuration.

Most of this change consist of shuffling the files around to reflect the new
organization.

We introduce `scudo_platform.h` where platform specific definition lie. This
involves the TSD model and the platform specific allocator parameters. In an
upcoming CL, those will be configurable via defines, but we currently stick
with conservative defaults.

Reviewers: alekseyshl, dvyukov

Reviewed By: alekseyshl, dvyukov

Subscribers: srhines, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D38244

llvm-svn: 314224
2017-09-26 17:20:02 +00:00