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| author |   Nicholas Bellinger <nab@linux-iscsi.org> | 2015-07-24 02:29:55 +0000 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-07-24 14:19:45 -0700 |
| commit | ce9a9fc20a78ad1e5222fae3a83d105f2d2fb9b9 (patch) | |
| tree | 50f1c9958f6dedce7e267eec61769744f797b949 /drivers/infiniband | |
| parent | iscsi-target: Fix iser explicit logout TX kthread leak (diff) | |
| download | linux-dev-ce9a9fc20a78ad1e5222fae3a83d105f2d2fb9b9.tar.xz linux-dev-ce9a9fc20a78ad1e5222fae3a83d105f2d2fb9b9.zip | |
iser-target: Fix REJECT CM event use-after-free OOPs
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>
Cc: <stable@vger.kernel.org> # v3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/infiniband')
| -rw-r--r-- | drivers/infiniband/ulp/isert/ib_isert.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c index 771700963127..d851e1828d6f 100644 --- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -775,6 +775,17 @@ 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->kref)) { + isert_warn("conn %p connect_release is running\n", isert_conn); + goto out_conn_dev; + } ret = isert_rdma_accept(isert_conn); if (ret) @@ -836,11 +847,6 @@ isert_connected_handler(struct rdma_cm_id *cma_id) isert_info("conn %p\n", isert_conn); - if (!kref_get_unless_zero(&isert_conn->kref)) { - isert_warn("conn %p connect_release is running\n", isert_conn); - return; - } - mutex_lock(&isert_conn->mutex); if (isert_conn->state != ISER_CONN_FULL_FEATURE) isert_conn->state = ISER_CONN_UP; |