OpenCloudOS-Kernel/drivers/android
Carlos Llamas a1d85fc6bd binder: fix hang of unregistered readers
commit 31643d84b8c3d9c846aa0e20bc033e46c68c7e7d upstream.

With the introduction of binder_available_for_proc_work_ilocked() in
commit 1b77e9dcc3 ("ANDROID: binder: remove proc waitqueue") a binder
thread can only "wait_for_proc_work" after its thread->looper has been
marked as BINDER_LOOPER_STATE_{ENTERED|REGISTERED}.

This means an unregistered reader risks waiting indefinitely for work
since it never gets added to the proc->waiting_threads. If there are no
further references to its waitqueue either the task will hang. The same
applies to readers using the (e)poll interface.

I couldn't find the rationale behind this restriction. So this patch
restores the previous behavior of allowing unregistered threads to
"wait_for_proc_work". Note that an error message for this scenario,
which had previously become unreachable, is now re-enabled.

Fixes: 1b77e9dcc3 ("ANDROID: binder: remove proc waitqueue")
Cc: stable@vger.kernel.org
Cc: Martijn Coenen <maco@google.com>
Cc: Arve Hjønnevåg <arve@google.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Link: https://lore.kernel.org/r/20240711201452.2017543-1-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-03 08:54:21 +02:00
..
Kconfig remove CONFIG_ANDROID 2022-07-01 10:41:09 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
binder.c binder: fix hang of unregistered readers 2024-08-03 08:54:21 +02:00
binder_alloc.c binder: fix race between mmput() and do_exit() 2024-01-25 15:35:42 -08:00
binder_alloc.h binder: fix memory leak in binder_init() 2023-08-04 15:25:01 +02:00
binder_alloc_selftest.c Revert "android: binder: stop saving a pointer to the VMA" 2023-05-13 20:30:16 +09:00
binder_internal.h binder: fix max_thread type inconsistency 2024-05-25 16:22:54 +02:00
binder_trace.h Binder: add TF_UPDATE_TXN to replace outdated txn 2022-06-27 16:16:30 +02:00
binderfs.c Char/Misc driver changes for 6.6-rc1 2023-09-01 09:53:54 -07:00