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)
committerMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Wed, 8 Jan 2020 13:37:28 +0000 (14:37 +0100)
commitbb6d42061a05d71dd73f620582d9e09c8fbf7f5b
tree09fae8a361e0f5d82ed60ec76a975c3f9332d009
parent11c48e41d5fcc5b4cf17aa74388be128ca5444f8
media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()

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>
drivers/media/platform/sti/bdisp/bdisp-hw.c