media: dvb-core: Fix kernel WARNING for blocking operation in wait_event*()
authorTakashi Iwai <tiwai@suse.de>
Fri, 12 May 2023 15:18:00 +0000 (16:18 +0100)
committerMauro Carvalho Chehab <mchehab@kernel.org>
Sun, 14 May 2023 06:33:31 +0000 (07:33 +0100)
commitb8c75e4a1b325ea0a9433fa8834be97b5836b946
tree7130e5c018a196a73e9b9b0935163818be2a5609
parent627bb528b086b4136315c25d6a447a98ea9448d3
media: dvb-core: Fix kernel WARNING for blocking operation in wait_event*()

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/
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>
drivers/media/dvb-core/dvb_frontend.c