From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Jia-Ju Bai <baijiaju1990@gmail.com>,
Fabien Dessenne <fabien.dessenne@st.com>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
Sasha Levin <sashal@kernel.org>,
linux-media@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 021/252] media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()
Date: Fri, 14 Feb 2020 11:07:56 -0500 [thread overview]
Message-ID: <20200214161147.15842-21-sashal@kernel.org> (raw)
In-Reply-To: <20200214161147.15842-1-sashal@kernel.org>
From: Jia-Ju Bai <baijiaju1990@gmail.com>
[ 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 | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c
index 26d9fa7aeb5f2..d57f659d740a1 100644
--- a/drivers/media/platform/sti/bdisp/bdisp-hw.c
+++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c
@@ -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");
--
2.20.1
next prev parent reply other threads:[~2020-02-14 17:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200214161147.15842-1-sashal@kernel.org>
2020-02-14 16:07 ` [PATCH AUTOSEL 4.19 005/252] media: i2c: adv748x: Fix unsafe macros Sasha Levin
2020-02-14 16:07 ` [PATCH AUTOSEL 4.19 015/252] media: i2c: mt9v032: fix enum mbus codes and frame sizes Sasha Levin
2020-02-14 16:07 ` Sasha Levin [this message]
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 092/252] media: cx23885: Add support for AVerMedia CE310B Sasha Levin
2020-02-14 16:09 ` [PATCH AUTOSEL 4.19 095/252] media: v4l2-device.h: Explicitly compare grp{id,mask} to zero in v4l2_device macros Sasha Levin
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