Linux-Hwmon Archive on lore.kernel.org
 help / color / Atom feed
From: Lei YU <mine260309@gmail.com>
To: Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	Eddie James <eajames@linux.ibm.com>,
	"Gustavo A . R . Silva" <gustavo@embeddedor.com>,
	Lei YU <mine260309@gmail.com>,
	linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] hwmon (occ): Fix division by zero issue
Date: Thu, 11 Jul 2019 10:44:48 +0800
Message-ID: <1562813088-23708-1-git-send-email-mine260309@gmail.com> (raw)

The code in occ_get_powr_avg() invokes div64_u64() without checking the
divisor. In case the divisor is zero, kernel gets an "Division by zero
in kernel" error.

Check the divisor and make it return 0 if the divisor is 0.

Signed-off-by: Lei YU <mine260309@gmail.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/hwmon/occ/common.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index 13a6290..f02aa40 100644
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -402,8 +402,10 @@ static ssize_t occ_show_power_1(struct device *dev,
 
 static u64 occ_get_powr_avg(u64 *accum, u32 *samples)
 {
-	return div64_u64(get_unaligned_be64(accum) * 1000000ULL,
-			 get_unaligned_be32(samples));
+	u64 divisor = get_unaligned_be32(samples);
+
+	return (divisor == 0) ? 0 :
+		div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor);
 }
 
 static ssize_t occ_show_power_2(struct device *dev,
-- 
2.7.4


             reply index

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-11  2:44 Lei YU [this message]
2019-07-11 16:35 ` Guenter Roeck

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=1562813088-23708-1-git-send-email-mine260309@gmail.com \
    --to=mine260309@gmail.com \
    --cc=eajames@linux.ibm.com \
    --cc=gustavo@embeddedor.com \
    --cc=jdelvare@suse.com \
    --cc=linux-hwmon@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@roeck-us.net \
    /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-Hwmon Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-hwmon/0 linux-hwmon/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-hwmon linux-hwmon/ https://lore.kernel.org/linux-hwmon \
		linux-hwmon@vger.kernel.org linux-hwmon@archiver.kernel.org
	public-inbox-index linux-hwmon


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


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