kernel_samsung_a53x/drivers/android
Carlos Llamas 0d5ae1ec66 binder: fix hang of unregistered readers
commit 31643d84b8c3d9c846aa0e20bc033e46c68c7e7d upstream.

With the introduction of binder_available_for_proc_work_ilocked() in
commit 1b77e9dcc3da ("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: 1b77e9dcc3da ("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>
2024-11-23 23:20:14 +01:00
..
binder.c binder: fix hang of unregistered readers 2024-11-23 23:20:14 +01:00
binder_alloc.c binder: fix race between mmput() and do_exit() 2024-11-18 12:12:45 +01:00
binder_alloc.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
binder_alloc_selftest.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
binder_internal.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
binder_trace.h Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
binderfs.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
debug_symbols.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
Kconfig Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
Makefile Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00
vendor_hooks.c Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00