[PATCHv1] xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.

[PATCHv1] xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.

[David Vrabel]

From: Jennifer Herbert <Jennifer.Herbert@citrix.com>

If Xenstore sends back a XS_ERROR for TRANSACTION_END, the driver BUGs
because it cannot find the matching transaction in the list.  For
TRANSACTION_START, it leaks memory.

Check the message as returned from xenbus_dev_request_and_reply(), and
clean up for TRANSACTION_START or discard the error for
TRANSACTION_END.

Signed-off-by: Jennifer Herbert <Jennifer.Herbert@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 drivers/xen/xenbus/xenbus_dev_frontend.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 85534ea..9433e46 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -326,10 +326,13 @@ static int xenbus_write_transaction(unsigned msg_type,
 	}
 
 	if (msg_type == XS_TRANSACTION_START) {
-		trans->handle.id = simple_strtoul(reply, NULL, 0);
-
-		list_add(&trans->list, &u->transactions);
-	} else if (msg_type == XS_TRANSACTION_END) {
+		if (u->u.msg.type == XS_ERROR)
+			kfree(trans);
+		else {
+			trans->handle.id = simple_strtoul(reply, NULL, 0);
+			list_add(&trans->list, &u->transactions);
+		}
+	} else if (u->u.msg.type == XS_TRANSACTION_END) {
 		list_for_each_entry(trans, &u->transactions, list)
 			if (trans->handle.id == u->u.msg.tx_id)
 				break;
-- 
1.7.10.4

Re: [PATCHv1] xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.

[David Vrabel]

On 05/02/15 15:02, David Vrabel wrote:
> From: Jennifer Herbert <Jennifer.Herbert@citrix.com>
> 
> If Xenstore sends back a XS_ERROR for TRANSACTION_END, the driver BUGs
> because it cannot find the matching transaction in the list.  For
> TRANSACTION_START, it leaks memory.
> 
> Check the message as returned from xenbus_dev_request_and_reply(), and
> clean up for TRANSACTION_START or discard the error for
> TRANSACTION_END.

Applied to devel/for-linus-3.20, thanks.

David

Re: [PATCHv1] xenbus: Add proper handling of XS_ERROR from Xenbus for transactions.

[Konrad Rzeszutek Wilk]

On Thu, Feb 05, 2015 at 03:07:59PM +0000, David Vrabel wrote:
> On 05/02/15 15:02, David Vrabel wrote:
> > From: Jennifer Herbert <Jennifer.Herbert@citrix.com>
> > 
> > If Xenstore sends back a XS_ERROR for TRANSACTION_END, the driver BUGs
> > because it cannot find the matching transaction in the list.  For
> > TRANSACTION_START, it leaks memory.
> > 
> > Check the message as returned from xenbus_dev_request_and_reply(), and
> > clean up for TRANSACTION_START or discard the error for
> > TRANSACTION_END.
> 
> Applied to devel/for-linus-3.20, thanks.

You are thanking yourself :-) ?

Maybe it is time for some vacation?
> 
> David
> 
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