netdev - [PATCH 02/12] can: cc770: Fix indirect access deadlock on ISA cards

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>] [day] [month] [year] [list]

Date:	Tue, 31 Jan 2012 22:46:40 +0100
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	linux-can@...r.kernel.org
Cc:	Wolfgang Zarre <lkdev@...ax.com>, netdev@...r.kernel.org,
	Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 02/12] can: cc770: Fix indirect access deadlock on ISA cards

From: Wolfgang Zarre <lkdev@...ax.com>

This fix avoids a deadlock if an interrupt occurs
during consecutive port operations on ISA cards
utilising indirect access via address and data
port.

Tested on a B&R ISA card.

CC: linux-can@...r.kernel.org
CC: netdev@...r.kernel.org
Signed-off-by: Wolfgang Zarre <lkdev@...ax.com>
Acked-by: Wolfgang Grandegger <wg@...ndegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/cc770/cc770_isa.c |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)

diff --git a/drivers/net/can/cc770/cc770_isa.c b/drivers/net/can/cc770/cc770_isa.c
index 4be5fe2..9f3a25c 100644
--- a/drivers/net/can/cc770/cc770_isa.c
+++ b/drivers/net/can/cc770/cc770_isa.c
@@ -110,6 +110,11 @@ MODULE_PARM_DESC(bcr, "Bus configuration register (default=0x40 [CBY])");
 #define CC770_IOSIZE          0x20
 #define CC770_IOSIZE_INDIRECT 0x02
 
+/* Spinlock for cc770_isa_port_write_reg_indirect
+ * and cc770_isa_port_read_reg_indirect
+ */
+static DEFINE_SPINLOCK(cc770_isa_port_lock);
+
 static struct platform_device *cc770_isa_devs[MAXDEV];
 
 static u8 cc770_isa_mem_read_reg(const struct cc770_priv *priv, int reg)
@@ -138,18 +143,27 @@ static u8 cc770_isa_port_read_reg_indirect(const struct cc770_priv *priv,
 					     int reg)
 {
 	unsigned long base = (unsigned long)priv->reg_base;
+	unsigned long flags;
+	u8 val;
 
+	spin_lock_irqsave(&cc770_isa_port_lock, flags);
 	outb(reg, base);
-	return inb(base + 1);
+	val = inb(base + 1);
+	spin_unlock_irqrestore(&cc770_isa_port_lock, flags);
+
+	return val;
 }
 
 static void cc770_isa_port_write_reg_indirect(const struct cc770_priv *priv,
 						int reg, u8 val)
 {
 	unsigned long base = (unsigned long)priv->reg_base;
+	unsigned long flags;
 
+	spin_lock_irqsave(&cc770_isa_port_lock, flags);
 	outb(reg, base);
 	outb(val, base + 1);
+	spin_unlock_irqrestore(&cc770_isa_port_lock, flags);
 }
 
 static int __devinit cc770_isa_probe(struct platform_device *pdev)
-- 
1.7.4.1

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html