[PATCH v2] binder: Prevent context manager from incrementing ref 0

[Sasha Levin]

Hi

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag
fixing commit: 457b9a6f09f0 ("Staging: android: add binder driver").

The bot has tested the following trees: v5.7.11, v5.4.54, v4.19.135, v4.14.190, v4.9.231, v4.4.231.

v5.7.11: Build OK!
v5.4.54: Build OK!
v4.19.135: Build OK!
v4.14.190: Build OK!
v4.9.231: Failed to apply! Possible dependencies:
    14db31814a9a ("binder: Deal with contexts in debugfs")
    19c987241ca1 ("binder: separate out binder_alloc functions")
    1b77e9dcc3da ("ANDROID: binder: remove proc waitqueue")
    342e5c90b601 ("binder: Support multiple context managers")
    408c68b17aea ("ANDROID: binder: push new transactions to waiting threads.")
    4bfac80af3a6 ("binder: Add extra size to allocator")
    512cf465ee01 ("binder: fix use-after-free in binder_transaction()")
    7980240b6d63 ("binder: Add support for scatter-gather")
    9630fe8839ba ("binder: introduce locking helper functions")
    a056af42032e ("binder: Refactor binder_transact()")
    ac4812c5ffbb ("binder: Support multiple /dev instances")
    def95c73567d ("binder: Add support for file-descriptor arrays")
    fdfb4a99b6ab ("binder: separate binder allocator structure from binder proc")
    feba3900cabb ("binder: Split flat_binder_object")

v4.4.231: Failed to apply! Possible dependencies:
    14db31814a9a ("binder: Deal with contexts in debugfs")
    19c987241ca1 ("binder: separate out binder_alloc functions")
    1b77e9dcc3da ("ANDROID: binder: remove proc waitqueue")
    212265e5ad72 ("android: binder: More offset validation")
    342e5c90b601 ("binder: Support multiple context managers")
    408c68b17aea ("ANDROID: binder: push new transactions to waiting threads.")
    4bfac80af3a6 ("binder: Add extra size to allocator")
    512cf465ee01 ("binder: fix use-after-free in binder_transaction()")
    7980240b6d63 ("binder: Add support for scatter-gather")
    83050a4e2197 ("android: drivers: Avoid debugfs race in binder")
    9630fe8839ba ("binder: introduce locking helper functions")
    a056af42032e ("binder: Refactor binder_transact()")
    a906d6931f3c ("android: binder: Sanity check at binder ioctl")
    ac4812c5ffbb ("binder: Support multiple /dev instances")
    def95c73567d ("binder: Add support for file-descriptor arrays")
    feba3900cabb ("binder: Split flat_binder_object")


NOTE: The patch will not be queued to stable trees until it is upstream.

How should we proceed with this patch?

-- 
Thanks
Sasha