@@ -686,6 +686,17 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
ret = isert_rdma_post_recvl(isert_conn);
if (ret)
goto out_conn_dev;
+ /*
+ * Obtain the second reference now before isert_rdma_accept() to
+ * ensure that any initiator generated REJECT CM event that occurs
+ * asynchronously won't drop the last reference until the error path
+ * in iscsi_target_login_sess_out() does it's ->iscsit_free_conn() ->
+ * isert_free_conn() -> isert_put_conn() -> kref_put().
+ */
+ if (!kref_get_unless_zero(&isert_conn->conn_kref)) {
+ isert_warn("conn %p connect_release is running\n", isert_conn);
+ goto out_conn_dev;
+ }
ret = isert_rdma_accept(isert_conn);
if (ret)
@@ -769,11 +780,6 @@ isert_connected_handler(struct rdma_cm_id *cma_id)
isert_info("conn %p\n", isert_conn);
- if (!kref_get_unless_zero(&isert_conn->conn_kref)) {
- isert_warn("conn %p connect_release is running\n", isert_conn);
- return;
- }
-
mutex_lock(&isert_conn->conn_mutex);
if (isert_conn->state != ISER_CONN_FULL_FEATURE)
isert_conn->state = ISER_CONN_UP;
This is a note to let you know that I have just added a patch titled iser-target: Fix REJECT CM event use-after-free OOPs to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt6. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From ed0c84332c3560eb249b0a381e11f04511d1a9da Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger <nab@linux-iscsi.org> Date: Fri, 24 Jul 2015 02:29:55 +0000 Subject: iser-target: Fix REJECT CM event use-after-free OOPs commit ce9a9fc20a78ad1e5222fae3a83d105f2d2fb9b9 upstream. This patch fixes a bug in iser-target code where the REJECT CM event handler code currently performs a isert_put_conn() for the final isert_conn->kref put, while iscsi_np process context is still blocked in isert_get_login_rx(). Once isert_get_login_rx() is awoking due to login timeout, iscsi_np process context will attempt to invoke iscsi_target_login_sess_out() to cleanup iscsi_conn as expected, and calls isert_wait_conn() + isert_free_conn() which triggers the use-after-free OOPs. To address this bug, move the kref_get_unless_zero() call from isert_connected_handler() into isert_connect_request() immediately preceeding isert_rdma_accept() to ensure the CM handler cleanup paths and isert_free_conn() are always operating with two refs. Cc: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> [ kamal: backport to 3.19-stable: context ] Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/infiniband/ulp/isert/ib_isert.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) -- 1.9.1