binder_alloc: add missing mmap_lock calls when using the VMA

binder_alloc: add missing mmap_lock calls when using the VMA

Take the mmap_read_lock() when using the VMA in binder_alloc_print_pages()
and when checking for a VMA in binder_alloc_new_buf_locked().

It is worth noting binder_alloc_new_buf_locked() drops the VMA read lock
after it verifies a VMA exists, but may be taken again deeper in the call
stack, if necessary.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: a43cfc87caaf (android: binder: stop saving a pointer to the VMA)
Signed-off-by: Liam R. Howlett <[email protected]>
Reported-by: Ondrej Mosnacek <[email protected]>
Reported-by: <[email protected]>
Acked-by: Carlos Llamas <[email protected]>
Tested-by: Ondrej Mosnacek <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Christian Brauner (Microsoft) <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Hridya Valsaraju <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Martijn Coenen <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Todd Kjos <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: "Arve Hjønnevåg" <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>