From e933b7be1c011205581e062d3925823dacef0cf4 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Fri, 12 May 2023 16:18:00 +0100
Subject: [PATCH] UPSTREAM: media: dvb-core: Fix kernel WARNING for blocking
 operation in wait_event*()

[ Upstream commit b8c75e4a1b325ea0a9433fa8834be97b5836b946 ]

Using a semaphore in the wait_event*() condition is no good idea.
It hits a kernel WARN_ON() at prepare_to_wait_event() like:
  do not call blocking ops when !TASK_RUNNING; state=1 set at
  prepare_to_wait_event+0x6d/0x690

For avoiding the potential deadlock, rewrite to an open-coded loop
instead.  Unlike the loop in wait_event*(), this uses wait_woken()
after the condition check, hence the task state stays consistent.

CVE-2023-31084 was assigned to this bug.

Link: https://lore.kernel.org/r/CA+UBctCu7fXn4q41O_3=id1+OdyQ85tZY1x+TkT-6OVBL6KAUw@mail.gmail.com/

Bug: 290204413
Link: https://lore.kernel.org/linux-media/20230512151800.1874-1-tiwai@suse.de
Reported-by: Yu Hao <yhao016@ucr.edu>
Closes: https://nvd.nist.gov/vuln/detail/CVE-2023-31084
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit d0088ea444e676a0c75551efe183bee4a3d2cfc8)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I1e715f6f1994e30781c1896c880b5491080f04da