Accessing the PLT entries of hooks can lead a certain amount of
performance overhead. This is observed on certain tasks which will do a
bunch of malloc/free and their throughputs are impacted by the null
check of hooks.
Also add SCUDO_ENABLE_HOOKS_TESTS to select if we want to run the hook
tests. On some platforms they may have different ways to run the
wrappers tests (end-to-end tests) and test the hooks along with the
wrappers tests may not be feasible. Provide an option to turn it ON/OFF.
By default, we only verify the hook behavior in the scudo standalone
tests if SCUDO_ENABLE_HOOKS is defined or COMPILER_RT_DEBUG is true.
Reviewed By: cferris, fabio-d
Differential Revision: https://reviews.llvm.org/D158784
Move the invocation of hooks from Scudo internal to wrapper_c.cpp and
wrapper_c_bionic.cpp respectively. Therefore, Scudo's core algorithm
doesnt need to worry about the reentrant of hooks and leave the caring
of reentrant to the hook users.
Reviewed By: hctim, cferris, chelfi
Differential Revision: https://reviews.llvm.org/D152188
This reverts commit 6911114d8cbed06a8a809c34ae07f4e3e89ab252.
Broke the QEMU sanitizer bots due to a missing header dependency. This
actually needs to be fixed on the bot-side, but for now reverting this
patch until I can fix up the bot.
This patch moves -fsanitize=scudo to link the standalone scudo library,
rather than the original compiler-rt based library. This is one of the
major remaining roadblocks to deleting the compiler-rt based scudo,
which should not be used any more. The standalone Scudo is better in
pretty much every way and is much more suitable for production usage.
As well as patching the litmus tests for checking that the
scudo_standalone lib is linked instead of the scudo lib, this patch also
ports all the scudo lit tests to run under scudo standalone.
This patch also adds a feature to scudo standalone that was under test
in the original scudo - that arguments passed to an aligned operator new
were checked that the alignment was a power of two.
Some lit tests could not be migrated, due to the following issues:
1. Features that aren't supported in scudo standalone, like the rss
limit.
2. Different quarantine implementation where the test needs some more
thought.
3. Small bugs in scudo standalone that should probably be fixed, like
the Secondary allocator having a full page on the LHS of an allocation
that only contains the chunk header, so underflows by <= a page aren't
caught.
4. Slight differences in behaviour that's technically correct, like
'realloc(malloc(1), 0)' returns nullptr in standalone, but a real
pointer in old scudo.
5. Some tests that might be migratable, but not easily.
Tests that are obviously not applicable to scudo standalone (like
testing that no sanitizer symbols made it into the DSO) have been
deleted.
After this patch, the remaining work is:
1. Update the Scudo documentation. The flags have changed, etc.
2. Delete the old version of scudo.
3. Patch up the tests in lit-unmigrated, or fix Scudo standalone.
Reviewed By: cryptoad, vitalybuka
Differential Revision: https://reviews.llvm.org/D102543
This lets us remove two pointer indirections (one by removing the pointer,
and another by making the AllocatorPtr declaration hidden) in the C++ wrappers.
Differential Revision: https://reviews.llvm.org/D74356
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
