diff options
| author | Jan Beulich <JBeulich@suse.com> | 2016-07-07 01:23:57 -0600 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-11-20 01:17:39 +0000 |
| commit | 266186df1d23ba855c1ad593947e2d51bd15f488 (patch) | |
| tree | a3a41488595e9c25bc8e694defa7b86b6e9b8eb4 | |
| parent | f11001c32a30af9bfb86d2b822ebef2e6d82d2db (diff) | |
| download | lwn-266186df1d23ba855c1ad593947e2d51bd15f488.tar.gz lwn-266186df1d23ba855c1ad593947e2d51bd15f488.zip | |
xenbus: don't BUG() on user mode induced condition
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@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Ed Swierk <eswierk@skyportsystems.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/xen/xenbus/xenbus_dev_frontend.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 85534ea63555..b9c791f228fe 100644 --- 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(unsigned msg_type, 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; } @@ -330,12 +337,7 @@ static int xenbus_write_transaction(unsigned msg_type, list_add(&trans->list, &u->transactions); } else if (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); } |