Commit Graph

6 Commits

Author SHA1 Message Date
Kostya Kortchinsky 612f23857f [scudo][standalone] Work with -Werror=class-memaccess
Summary:
Fuchsia's gcc uses this, which in turn prevents us to compile successfully
due to a few `memset`'ing some non-trivial classes in some `init`.

Change those `memset` to members initialization.

Reviewers: pcc, hctim

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D77902
2020-04-11 07:29:12 -07:00
Kostya Kortchinsky 9ef6faf496 [scudo][standalone] Fork support
Summary:
fork() wasn't well (or at all) supported in Scudo. This materialized
in deadlocks in children.

In order to properly support fork, we will lock the allocator pre-fork
and unlock it post-fork in parent and child. This is done via a
`pthread_atfork` call installing the necessary handlers.

A couple of things suck here: this function allocates - so this has to
be done post initialization as our init path is not reentrance, and it
doesn't allow for an extra pointer - so we can't pass the allocator we
are currently working with.

In order to work around this, I added a post-init template parameter
that gets executed once the allocator is initialized for the current
thread. Its job for the C wrappers is to install the atfork handlers.

I reorganized a bit the impacted area and added some tests, courtesy
of cferris@ that were deadlocking prior to this fix.

Subscribers: jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D72470
2020-01-14 07:51:48 -08:00
Kostya Kortchinsky 6f2de9cbb3 [scudo][standalone] Consolidate lists
Summary:
This is a clean patch using the last diff of D69265, but using git
instead of svn, since svn went ro and arc was making my life harded
than it needed to be.

I was going to introduce a couple more lists and realized that our
lists are currently a bit all over the place. While we have a singly
linked list type relatively well defined, we are using doubly linked
lists defined on the fly for the stats and for the secondary blocks.

This CL adds a doubly linked list object, reorganizing the singly list
one to extract as much of the common code as possible. We use this
new type in the stats and the secondary. We also reorganize the list
tests to benefit from this consolidation.

There are a few side effect changes such as using for iterator loops
that are, in my opinion, cleaner in a couple of places.

Reviewers: hctim, morehouse, pcc, cferris

Reviewed By: hctim

Subscribers: jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D69516
2019-10-28 09:34:36 -07:00
Kostya Kortchinsky 2be59170d4 [scudo][standalone] Add more stats to mallinfo
Summary:
Android requires additional stats in mallinfo. While we can provide
right away the number of bytes mapped (Primary+Secondary), there was
no way to get the number of free bytes (only makes sense for the
Primary since the Secondary unmaps everything on deallocation).

An approximation could be `StatMapped - StatAllocated`, but since we
are mapping in `1<<17` increments for the 64-bit Primary, it's fairly
inaccurate.

So we introduce `StatFree` (note it's `Free`, not `Freed`!), which
keeps track of the amount of Primary blocks currently unallocated.

Reviewers: cferris, eugenis, vitalybuka, hctim, morehouse

Reviewed By: morehouse

Subscribers: delcypher, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D66112

llvm-svn: 368866
2019-08-14 16:04:01 +00:00
Kostya Kortchinsky aeb3826228 [scudo][standalone] Merge Spin & Blocking mutex into a Hybrid one
Summary:
We ran into a problem on Fuchsia where yielding threads would never
be deboosted, ultimately resulting in several threads spinning on the
same TSD, and no possibility for another thread to be scheduled,
dead-locking the process.

While this was fixed in Zircon, this lead to discussions about if
spinning without a break condition was a good decision, and settled on
a new hybrid model that would spin for a while then block.

Currently we are using a number of iterations for spinning that is
mostly arbitrary (based on sanitizer_common values), but this can
be tuned in the future.

Since we are touching `common.h`, we also use this change as a vehicle
for an Android optimization (the page size is fixed in Bionic, so use
a fixed value too).

Reviewers: morehouse, hctim, eugenis, dvyukov, vitalybuka

Reviewed By: hctim

Subscribers: srhines, delcypher, jfb, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D64358

llvm-svn: 365790
2019-07-11 15:32:26 +00:00
Kostya Kortchinsky 16d9a3a4b6 [scudo][standalone] Adding a stats class
Summary:
This adds simple local & global stats classes to be used by the Primary
and Secondary, and associated test. Note that we don't need the strict
atomicity of the addition & subtraction (as is in sanitizer_common) so
we just use load & store.

Reviewers: morehouse, vitalybuka, eugenis, flowerhack, dmmoore415

Reviewed By: morehouse, vitalybuka

Subscribers: mgorny, delcypher, jfb, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D59031

llvm-svn: 355643
2019-03-07 21:44:35 +00:00