Expecting the memory in a forked child process to be sane wrt threading
is a bad idea. An example of a problem is when the parent process has
the malloc lock and a child process is forked. The malloc lock in the
child will appear locked by a thread that doesn't exist.
This change aims to make bionic more compatible with glibc by reseting
the malloc lock in the child forked process, as well as holding it
during the fork. This is a feature in dlmalloc 2.8.6 called
LOCK_AT_FORK. In general this feature isn't necessary as a forked
process will then exec. Some bad applications rely on being able to use
features like malloc before the exec and having multiple threads running
in the parent program. This isn't a problem with glibc and this patch
makes it not a problem for bionic.
Unfortunately for use in bionic, LOCK_AT_FORK has an issue as internally
it uses pthread_atfork that in bionic uses malloc. This leads to the
LOCK_AT_FORK initialization deadlocking with pthread_atfork's call to
malloc due to the malloc lock. This change moves the pthread_atfork logic
in LOCK_AT_FORK to be called without the malloc lock held.
Change-Id: Id68175a564a6abb936ee4488b44d9479f7311f69
Move dlmalloc code to upstream-dlmalloc to make pulling upstream changes
easier.
Declare pvalloc and malloc_usable_size routines present in malloc.h but with
missing implementations. Remove other functions from malloc.h that have
no implementation nor use in Android.
Change-Id: Ia6472ec6cbebc9ad1ef99f4669de9d33fcc2efb4
This change is intended to eliminate need to replace libc.so with libc_debug.so in order to enablememory allocation debugging.
This is also the first step towards implementing extended memoryallocation debugging using emulator's capabilities in monitoring memory access.
