binder: Address corner cases in deferred copy and fixup

When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().

This is reproducible in android when playing a video.
We receive a transaction that looks like this:
    obj[0] BINDER_TYPE_PTR, parent
    obj[1] BINDER_TYPE_PTR, child
    obj[2] BINDER_TYPE_PTR, child
    obj[3] BINDER_TYPE_FDA, child

Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Alessandro Astone <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions