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media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()

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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>
This commit is contained in:
Jia-Ju Bai 2019-12-19 11:34:01 +01:00 committed by Mauro Carvalho Chehab
parent 11c48e41d5
commit bb6d42061a
1 changed files with 3 additions and 3 deletions
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6
drivers/media/platform/sti/bdisp/bdisp-hw.c
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@ -14,8 +14,8 @@
#define MAX_SRC_WIDTH 2048
/* Reset & boot poll config */
#define POLL_RST_MAX 50
#define POLL_RST_DELAY_MS 20
#define POLL_RST_MAX 500
#define POLL_RST_DELAY_MS 2
enum bdisp_target_plan {
BDISP_RGB,
@ -382,7 +382,7 @@ int bdisp_hw_reset(struct bdisp_dev *bdisp)
for (i = 0; i < POLL_RST_MAX; i++) {
if (readl(bdisp->regs + BLT_STA1) & BLT_STA1_IDLE)
break;
msleep(POLL_RST_DELAY_MS);
udelay(POLL_RST_DELAY_MS * 1000);
}
if (i == POLL_RST_MAX)
dev_err(bdisp->dev, "Reset timeout\n");