[GIT PULL] SCSI fixes for 5.12-rc

From: James Bottomley
Date: Fri Apr 02 2021 - 20:34:32 EST


Single fix to iscsi for a rare race condition which can cause a kernel
panic.

The patch is available here:

git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git scsi-fixes

The short changelog is:

Gulam Mohamed (1):
scsi: iscsi: Fix race condition between login and sync thread

And the diffstat:

drivers/scsi/scsi_transport_iscsi.c | 14 +++++++++++++-
include/scsi/scsi_transport_iscsi.h | 1 +
2 files changed, 14 insertions(+), 1 deletion(-)

With full diff below.

James

---

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 969d24d580e2..bebfb355abdf 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -2471,6 +2471,7 @@ static void iscsi_if_stop_conn(struct iscsi_cls_conn *conn, int flag)
*/
mutex_lock(&conn_mutex);
conn->transport->stop_conn(conn, flag);
+ conn->state = ISCSI_CONN_DOWN;
mutex_unlock(&conn_mutex);

}
@@ -2894,6 +2895,13 @@ iscsi_set_param(struct iscsi_transport *transport, struct iscsi_uevent *ev)
default:
err = transport->set_param(conn, ev->u.set_param.param,
data, ev->u.set_param.len);
+ if ((conn->state == ISCSI_CONN_BOUND) ||
+ (conn->state == ISCSI_CONN_UP)) {
+ err = transport->set_param(conn, ev->u.set_param.param,
+ data, ev->u.set_param.len);
+ } else {
+ return -ENOTCONN;
+ }
}

return err;
@@ -2953,6 +2961,7 @@ static int iscsi_if_ep_disconnect(struct iscsi_transport *transport,
mutex_lock(&conn->ep_mutex);
conn->ep = NULL;
mutex_unlock(&conn->ep_mutex);
+ conn->state = ISCSI_CONN_DOWN;
}

transport->ep_disconnect(ep);
@@ -3713,6 +3722,8 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
ev->r.retcode = transport->bind_conn(session, conn,
ev->u.b_conn.transport_eph,
ev->u.b_conn.is_leading);
+ if (!ev->r.retcode)
+ conn->state = ISCSI_CONN_BOUND;
mutex_unlock(&conn_mutex);

if (ev->r.retcode || !transport->ep_connect)
@@ -3944,7 +3955,8 @@ iscsi_conn_attr(local_ipaddr, ISCSI_PARAM_LOCAL_IPADDR);
static const char *const connection_state_names[] = {
[ISCSI_CONN_UP] = "up",
[ISCSI_CONN_DOWN] = "down",
- [ISCSI_CONN_FAILED] = "failed"
+ [ISCSI_CONN_FAILED] = "failed",
+ [ISCSI_CONN_BOUND] = "bound"
};

static ssize_t show_conn_state(struct device *dev,
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index 8a26a2ffa952..fc5a39839b4b 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -193,6 +193,7 @@ enum iscsi_connection_state {
ISCSI_CONN_UP = 0,
ISCSI_CONN_DOWN,
ISCSI_CONN_FAILED,
+ ISCSI_CONN_BOUND,
};

struct iscsi_cls_conn {