When enabled, GWP-ASan sets the current dispatch table. Then, when a
shim layer (malloc_debug, malloc_hooks, heapprofd) comes along, they
should (by design) overwrite the current dispatch table.
Currently, these shim layers check to see whether malloc_limit is
installed by checking the current dispatch table against nullptr.
Because GWP-ASan owns the current dispatch table, the shim thinks that
malloc_limit is installed and falls back to only use the default
dispatch, thinking that malloc_limit will call them. This is not the
case, and they should take over the current dispatch pointer.
Bug: 135634846
Test: atest bionic
Change-Id: Ifb6f8864a15af9ac7f20d9364c40f73c5dd9d870
This patch refactors heapprofd_malloc to make it easier to reuse the
reserved signal for multiple purposes. We define a new generic signal
handler for profilers, which dispatches to more specific logic based on
the signal's payload (si_value).
The profiler signal handler is installed during libc preinit, after
malloc initialization (so races against synchronous heapprofd
initialization need not be considered). In terms of code organization, I
copied the existing approach with a loosely referenced function in
bionic_globals.h. Do tell if you'd rather a different approach here.
The profileability of a process is quite tied to the malloc
files/interfaces in bionic - in particular, it's set through
android_mallopt. I do not change that, but instead introduce a new
android_mallopt option to be able to query profileability of the
process (which is now used by the new profiler signal handler). As part
of that, gZygoteChildProfileable is moved from heapprofd_malloc to
common (alongside gZygoteChild).
I've removed the masking and reraising of the heapprofd signal when
racing against malloc_limit init. We're ok with taking a simpler
approach and dropping the heapprofd signal in such an unlikely race.
Note: this requires a corresponding change in heapprofd to use sigqueue()
instead of kill(), as the latter leaves the si_value uninitialized(?) on
the receiving side.
Bug: 144281346
Change-Id: I93bb2e82cff5870e5ca499cf86439860aca9dfa5
I have no idea why I used the iterate name internally which is
completely unlike every other function name. Change this to match
everyone else so that it's now malloc_iterate everywhere.
This is probably the last chance to change this before mainline
modules begin, so make everything consistent.
Test: Compiles, unit tests passes.
Change-Id: I56d293377fa0fe1a3dc3dd85d6432f877cc2003c
Bug: 128872105
Test: Ran the android_mallopt.set_allocation_limit_multiple_threads test
Test: a thousand times on taimen.
Change-Id: I67a474c53cd6eda8106feac99aee8e7b0bee1254
Introduce an M_SET_ALLOCATION_LIMIT enumerator for android_mallopt(),
which can be used to set an upper bound on the total size of all
allocations made using the memory allocation APIs.
This is useful for programs such as audioextractor and mediaserver
which need to set such a limit as a security mitigation. Currently
these programs are using setrlimit(RLIMIT_AS) which isn't exactly
what these programs want to control. RLIMIT_AS is also problematic
under sanitizers which allocate large amounts of address space as
shadow memory, and is especially problematic under shadow call stack,
which requires 16MB of address space per thread.
Add new unit tests for bionic.
Add new unit tests for malloc debug that verify that when the limit
is enabled, malloc debug still functions for nearly every allocation
function.
Bug: 118642754
Test: Ran bionic-unit-tests/bionic-unit-tests-static.
Test: Ran malloc debug tests and perfetto integration tests.
Change-Id: I735403c4d2c87f00fb2cdef81d00af0af446b2bb
