The free track mechanism could fail if, at the same time a free occurs,
another thread is trying to free and verify the same allocation. This
doesn't work if the freed allocation is added to the list and we still
do work on it. The fix is to only add to the free list when we are done
with the allocation.
Also fix a problem where the usable size is computed incorrectly because
two of the arguments where reversed.
In addition, add a check that the allocation being verified has the correct
tag before trying to check the body of the allocation.
Add a test to catch the original failure.
Add a test for the tag being different.
Bug: 27601650
Change-Id: Ie9200677d066255b8e668a48422f23f909f4ddee
Included in this change:
- Change the tag when a pointer is freed so it's easy to detect if
an already freed pointer is being used.
- Move the free backtrace out of the header. This backtrace is only
used under only some circumstances, so no need to allocate space
in all headers for it.
- Add new option free_track_backtrace_num_frames to specify how many
frames to record when the free occurs. This removes the dependency
on the backtrace option to get backtraces.
Bug: 26739265
Change-Id: I76f5209507dcf46af67ada162a7cb2bf282116f2
The major components of the rewrite:
- Completely remove the qemu shared library code. Nobody was using it
and it appears to have broken at some point.
- Adds the ability to enable/disable different options independently.
- Adds a new option that can enable the backtrace on alloc/free when
a process gets a specific signal.
- Adds a new way to enable malloc debug. If a special property is
set, and the process has an environment variable set, then debug
malloc will be enabled. This allows something that might be
a derivative of app_process to be started with an environment variable
being enabled.
- get_malloc_leak_info() used to return one element for each pointer that
had the exact same backtrace. The new version returns information for
every one of the pointers with same backtrace. It turns out ddms already
automatically coalesces these, so the old method simply hid the fact
that there where multiple pointers with the same amount of backtrace.
- Moved all of the malloc debug specific code into the library.
Nothing related to the malloc debug data structures remains in libc.
- Removed the calls to the debug malloc cleanup routine. Instead, I
added an atexit call with the debug malloc cleanup routine. This gets
around most problems related to the timing of doing the cleanup.
The new properties and environment variables:
libc.debug.malloc.options
Set by option name (such as "backtrace"). Setting this to a bad value
will cause a usage statement to be printed to the log.
libc.debug.malloc.program
Same as before. If this is set, then only the program named will
be launched with malloc debug enabled. This is not a complete match,
but if any part of the property is in the program name, malloc debug is
enabled.
libc.debug.malloc.env_enabled
If set, then malloc debug is only enabled if the running process has the
environment variable LIBC_DEBUG_MALLOC_ENABLE set.
Bug: 19145921
Change-Id: I7b0e58cc85cc6d4118173fe1f8627a391b64c0d7
