This is a note to let you know that I've just added the patch titled
xenbus: don't BUG() on user mode induced condition
to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xenbus-don-t-bug-on-user-mode-induced-condition.patch
and it can be found in the queue-4.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0beef634b86a1350c31da5fcc2992f0d7c8a622b Mon Sep 17 00:00:00 2001
From: Jan Beulich <JBeulich@xxxxxxxx>
Date: Thu, 7 Jul 2016 01:23:57 -0600
Subject: xenbus: don't BUG() on user mode induced condition
From: Jan Beulich <JBeulich@xxxxxxxx>
commit 0beef634b86a1350c31da5fcc2992f0d7c8a622b upstream.
Inability to locate a user mode specified transaction ID should not
lead to a kernel crash. For other than XS_TRANSACTION_START also
don't issue anything to xenbus if the specified ID doesn't match that
of any active transaction.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/xen/xenbus/xenbus_dev_frontend.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -316,11 +316,18 @@ static int xenbus_write_transaction(unsi
rc = -ENOMEM;
goto out;
}
+ } else {
+ list_for_each_entry(trans, &u->transactions, list)
+ if (trans->handle.id == u->u.msg.tx_id)
+ break;
+ if (&trans->list == &u->transactions)
+ return -ESRCH;
}
reply = xenbus_dev_request_and_reply(&u->u.msg);
if (IS_ERR(reply)) {
- kfree(trans);
+ if (msg_type == XS_TRANSACTION_START)
+ kfree(trans);
rc = PTR_ERR(reply);
goto out;
}
@@ -333,12 +340,7 @@ static int xenbus_write_transaction(unsi
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;
- BUG_ON(&trans->list == &u->transactions);
list_del(&trans->list);
-
kfree(trans);
}
Patches currently in stable-queue which might be from JBeulich@xxxxxxxx are
queue-4.6/xen-pciback-fix-conf_space-read-write-overlap-check.patch
queue-4.6/xenbus-don-t-bail-early-from-xenbus_dev_request_and_reply.patch
queue-4.6/xenbus-don-t-bug-on-user-mode-induced-condition.patch
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