media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()
authorJia-Ju Bai <baijiaju1990@gmail.com>
Thu, 19 Dec 2019 10:34:01 +0000 (11:34 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 24 Feb 2020 07:34:36 +0000 (08:34 +0100)
commit47505a7debe76f07c81071c009f2c05bb7f99959
treecc2a0eda4a5ebf882aea1d88c692cffad2570fd9
parent15341b1dd409749fa5625e4b632013b6ba81609b
media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()

[ Upstream commit bb6d42061a05d71dd73f620582d9e09c8fbf7f5b ]

The driver may sleep while holding a spinlock.
The function call path (from bottom to top) in Linux 4.19 is:

drivers/media/platform/sti/bdisp/bdisp-hw.c, 385:
    msleep in bdisp_hw_reset
drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 341:
    bdisp_hw_reset in bdisp_device_run
drivers/media/platform/sti/bdisp/bdisp-v4l2.c, 317:
    _raw_spin_lock_irqsave in bdisp_device_run

To fix this bug, msleep() is replaced with udelay().

This bug is found by a static analysis tool STCheck written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/media/platform/sti/bdisp/bdisp-hw.c