linux-kernel - [PATCH] mfd: viperboard: allocate I/O buffer separately

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1411397212-31625-1-git-send-email-octavian.purdila@intel.com>
Date:	Mon, 22 Sep 2014 17:46:52 +0300
From:	Octavian Purdila <octavian.purdila@...el.com>
To:	sameo@...ux.intel.com, lee.jones@...aro.org
Cc:	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	Octavian Purdila <octavian.purdila@...el.com>
Subject: [PATCH] mfd: viperboard: allocate I/O buffer separately

Currently the I/O buffer is allocated part of the device status
structure, potentially sharing the same cache line with other members
in this structure.

Allocate the buffer separately, to avoid the I/O operations corrupting
the device status structure due to cache line sharing.

Compiled tested only, as I don't have access to hardware.

Signed-off-by: Octavian Purdila <octavian.purdila@...el.com>
---
 drivers/mfd/viperboard.c       | 16 ++++++++++------
 include/linux/mfd/viperboard.h |  2 +-
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/mfd/viperboard.c b/drivers/mfd/viperboard.c
index e00f534..d27c131 100644
--- a/drivers/mfd/viperboard.c
+++ b/drivers/mfd/viperboard.c
@@ -59,9 +59,13 @@ static int vprbrd_probe(struct usb_interface *interface,
 
 	/* allocate memory for our device state and initialize it */
 	vb = kzalloc(sizeof(*vb), GFP_KERNEL);
-	if (vb == NULL) {
-		dev_err(&interface->dev, "Out of memory\n");
+	if (vb == NULL)
 		return -ENOMEM;
+
+	vb->buf = kzalloc(sizeof(struct vprbrd_i2c_write_msg), GFP_KERNEL);
+	if (vb->buf == NULL) {
+		ret = -ENOMEM;
+		goto error;
 	}
 
 	mutex_init(&vb->lock);
@@ -103,10 +107,9 @@ static int vprbrd_probe(struct usb_interface *interface,
 	return 0;
 
 error:
-	if (vb) {
-		usb_put_dev(vb->usb_dev);
-		kfree(vb);
-	}
+	usb_put_dev(vb->usb_dev);
+	kfree(vb->buf);
+	kfree(vb);
 
 	return ret;
 }
@@ -118,6 +121,7 @@ static void vprbrd_disconnect(struct usb_interface *interface)
 	mfd_remove_devices(&interface->dev);
 	usb_set_intfdata(interface, NULL);
 	usb_put_dev(vb->usb_dev);
+	kfree(vb->buf);
 	kfree(vb);
 
 	dev_dbg(&interface->dev, "disconnected\n");
diff --git a/include/linux/mfd/viperboard.h b/include/linux/mfd/viperboard.h
index 1934528..af928d0 100644
--- a/include/linux/mfd/viperboard.h
+++ b/include/linux/mfd/viperboard.h
@@ -103,7 +103,7 @@ struct vprbrd_i2c_addr_msg {
 struct vprbrd {
 	struct usb_device *usb_dev; /* the usb device for this device */
 	struct mutex lock;
-	u8 buf[sizeof(struct vprbrd_i2c_write_msg)];
+	u8 *buf;
 	struct platform_device pdev;
 };
 
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/