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ae4ea9a246
Commit 7ea0ed2b5be8 ("ipmi: Make the message handler easier to use for
SMI interfaces") changed handle_new_recv_msgs() to call handle_one_recv_msg()
for a smi_msg while the smi_msg is still connected to waiting_rcv_msgs list.
That could lead to following list corruption problems:
1) low-level function treats smi_msg as not connected to list
handle_one_recv_msg() could end up calling smi_send(), which
assumes the msg is not connected to list.
For example, the following sequence could corrupt list by
doing list_add_tail() for the entry still connected to other list.
handle_new_recv_msgs()
msg = list_entry(waiting_rcv_msgs)
handle_one_recv_msg(msg)
handle_ipmb_get_msg_cmd(msg)
smi_send(msg)
spin_lock(xmit_msgs_lock)
list_add_tail(msg)
spin_unlock(xmit_msgs_lock)
2) race between multiple handle_new_recv_msgs() instances
handle_new_recv_msgs() once releases waiting_rcv_msgs_lock before calling
handle_one_recv_msg() then retakes the lock and list_del() it.
If others call handle_new_recv_msgs() during the window shown below
list_del() will be done twice for the same smi_msg.
handle_new_recv_msgs()
spin_lock(waiting_rcv_msgs_lock)
msg = list_entry(waiting_rcv_msgs)
spin_unlock(waiting_rcv_msgs_lock)
|
| handle_one_recv_msg(msg)
|
spin_lock(waiting_rcv_msgs_lock)
list_del(msg)
spin_unlock(waiting_rcv_msgs_lock)
Fixes: 7ea0ed2b5be8 ("ipmi: Make the message handler easier to use for SMI interfaces")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
[Added a comment to describe why this works.]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: stable@vger.kernel.org # 3.19
Tested-by: Ye Feng <yefeng.yl@alibaba-inc.com>