Linux-Media Archive on lore.kernel.org
 help / color / Atom feed
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 5.5 055/542] media: sti: bdisp: fix a possible sleep-in-atomic-context bug in bdisp_device_run()
Date: Fri, 14 Feb 2020 10:40:47 -0500
Message-ID: <20200214154854.6746-55-sashal@kernel.org> (raw)
In-Reply-To: <20200214154854.6746-1-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 4372abbb5950f..a74e9fd652389 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


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200214154854.6746-1-sashal@kernel.org>
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 018/542] media: i2c: adv748x: Fix unsafe macros Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 019/542] media: meson: add missing allocation failure check on new_buf Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 041/542] media: ov5640: Fix check for PLL1 exceeding max allowed rate Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 042/542] media: i2c: mt9v032: fix enum mbus codes and frame sizes Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 043/542] media: sun4i-csi: Deal with DRAM offset Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 044/542] media: sun4i-csi: Fix data sampling polarity handling Sasha Levin
2020-02-14 15:40 ` [PATCH AUTOSEL 5.5 046/542] media: sun4i-csi: Fix [HV]sync " Sasha Levin
2020-02-14 15:40 ` Sasha Levin [this message]
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 204/542] media: cx23885: Add support for AVerMedia CE310B Sasha Levin
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 210/542] media: v4l2-device.h: Explicitly compare grp{id,mask} to zero in v4l2_device macros Sasha Levin
2020-02-14 15:47 ` [PATCH AUTOSEL 5.5 447/542] media: uvcvideo: Add a quirk to force GEO GC6500 Camera bits-per-pixel value Sasha Levin

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200214154854.6746-55-sashal@kernel.org \
    --to=sashal@kernel.org \
    --cc=baijiaju1990@gmail.com \
    --cc=fabien.dessenne@st.com \
    --cc=hverkuil-cisco@xs4all.nl \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=mchehab+huawei@kernel.org \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Media Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-media/0 linux-media/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-media linux-media/ https://lore.kernel.org/linux-media \
		linux-media@vger.kernel.org
	public-inbox-index linux-media

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-media


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git