IssueTracker

This issue occur on Android L version.

steps to reproduce:
1.enable libc.debug.malloc 1 for all process throght the property seting as below
adb shell "echo libc.debug.malloc=1 >> /data/local.prop"
adb shell "chmod 644 /data/local.prop"
adb reboot
2.after phone reboot run monkey test or free test, sometimes deadlock occur, bactrace maybe as below: child process block on mutex
  #00 pc 0000000000019c58  /system/lib64/libc.so (syscall+28)
  #01 pc 00000000000201dc  /system/lib64/libc.so (pthread_mutex_lock+148)
  #02 pc 000000000000316c  /system/lib64/libc_malloc_debug_leak.so
  #03 pc 00000000000197d4  /system/lib64/libc.so (malloc+20)

expected:
system can run smoothly

Issue root cause:
malloc_debug_leak.cpp leak_malloc/leak_free get g_hash_table->lock in parent process then fork child process, due to mutex in lock state and can't release, so child process can't get the mutex and block forever.

Suggest fix method:
register pthread_atfork callback to sync the g_hash_table->lock.