Commit bb6d4206 authored by Jia-Ju Bai's avatar Jia-Ju Bai Committed by Mauro Carvalho Chehab
Browse files

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: default avatarJia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: default avatarFabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
parent 11c48e41

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

+3 −3
Original line number Diff line number Diff line
@@ -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");