sseepsse/android_kernel_motorola_omap4-common — pull request #1 by sseepsse (2013-08-10 01:12:08+00:00)
Title: ashmem: avoid deadlock between read and mmap calls

Avoid holding ashmem_mutex across code that can page fault. Page faults
grab the mmap_sem for the process, which are also held by mmap calls
prior to calling ashmem_mmap, which locks ashmem_mutex. The reversed
order of locking between the two can deadlock.

The calls that can page fault are read() and the ASHMEM_SET_NAME and
ASHMEM_GET_NAME ioctls. Move the code that accesses userspace pages
outside the ashmem_mutex.

Bug: 9261835
Change-Id: If1322e981d29c889a56cdc9dfcbc6df2729a45e9
Signed-off-by: Todd Poynor