From: Jia-Ju Bai <baijiaju1990@gmail.com>
To: fabien.dessenne@st.com, mchehab@kernel.org
Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()
Date: Wed, 18 Dec 2019 22:05:37 +0800 [thread overview]
Message-ID: <20191218140537.12193-1-baijiaju1990@gmail.com> (raw)
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 mdelay().
This bug is found by a static analysis tool STCheck written by myself.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/media/platform/sti/bdisp/bdisp-hw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c
index 4372abbb5950..1a56348805a2 100644
--- a/drivers/media/platform/sti/bdisp/bdisp-hw.c
+++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c
@@ -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);
+ mdelay(POLL_RST_DELAY_MS);
}
if (i == POLL_RST_MAX)
dev_err(bdisp->dev, "Reset timeout\n");
--
2.17.1
next reply other threads:[~2019-12-18 14:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 14:05 Jia-Ju Bai [this message]
2019-12-19 9:01 ` Fabien DESSENNE
2019-12-19 9:14 ` Fabien DESSENNE
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