From: Stefan Richter on
Date: Mon, 14 Jun 2010 11:46:25 +0200
From: Clemens Ladisch <clemens(a)ladisch.de>

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(a)ladisch.de>
Signed-off-by: Stefan Richter <stefanr(a)s5r6.in-berlin.de>
---
drivers/firewire/core-cdev.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

Index: b/drivers/firewire/core-cdev.c
===================================================================
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -865,10 +865,6 @@ static int ioctl_create_iso_context(stru
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;

@@ -893,10 +889,17 @@ static int ioctl_create_iso_context(stru
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;

--
Stefan Richter
-=====-==-=- -==- =-=--
http://arcgraph.de/sr/

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