From bdfe273ee54b29498851fc8058516037d284270c Mon Sep 17 00:00:00 2001
From: Clemens Ladisch <clemens@ladisch.de>
Date: Mon, 14 Jun 2010 11:46:25 +0200
Subject: [PATCH] firewire: cdev: fix race in iso context creation
Protect the client's iso context pointer against a race that can happen
when more than one creation call is executed at the same time.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
drivers/firewire/core-cdev.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 4e0478d70d4d..ce8cb6fcbbcd 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -864,10 +864,6 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
struct fw_cdev_create_iso_context *a = &arg->create_iso_context;
struct fw_iso_context *context;
- /* We only support one context at this time. */
- if (client->iso_context != NULL)
- return -EBUSY;
-
if (a->channel > 63)
return -EINVAL;
@@ -892,10 +888,17 @@ static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
if (IS_ERR(context))
return PTR_ERR(context);
+ /* We only support one context at this time. */
+ spin_lock_irq(&client->lock);
+ if (client->iso_context != NULL) {
+ spin_unlock_irq(&client->lock);
+ fw_iso_context_destroy(context);
+ return -EBUSY;
+ }
client->iso_closure = a->closure;
client->iso_context = context;
+ spin_unlock_irq(&client->lock);
- /* We only support one context at this time. */
a->handle = 0;
return 0;
--
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