From d02a5e6c2fba8b114c44cf05085fca07180f37f1 Mon Sep 17 00:00:00 2001 From: Michael Chan Date: Wed, 24 Feb 2010 14:42:06 +0000 Subject: [PATCH] cnic: Fix panic in cnic_iscsi_nl_msg_recv() when device is down. Some data structures are freed when the device is down and it will crash if an ISCSI netlink message is received. Add RCU protection to prevent this. In the shutdown path, ulp_ops[CNIC_ULP_L4] is assigned NULL and rcu_synchronized before freeing the data structures. Signed-off-by: Michael Chan Signed-off-by: David S. Miller --- drivers/net/cnic.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/cnic.c b/drivers/net/cnic.c index 40865aac2afa..45584442a35c 100644 --- a/drivers/net/cnic.c +++ b/drivers/net/cnic.c @@ -327,6 +327,12 @@ static int cnic_iscsi_nl_msg_recv(struct cnic_dev *dev, u32 msg_type, if (l5_cid >= MAX_CM_SK_TBL_SZ) break; + rcu_read_lock(); + if (!rcu_dereference(cp->ulp_ops[CNIC_ULP_L4])) { + rc = -ENODEV; + rcu_read_unlock(); + break; + } csk = &cp->csk_tbl[l5_cid]; csk_hold(csk); if (cnic_in_use(csk)) { @@ -341,6 +347,7 @@ static int cnic_iscsi_nl_msg_recv(struct cnic_dev *dev, u32 msg_type, cnic_cm_set_pg(csk); } csk_put(csk); + rcu_read_unlock(); rc = 0; } } -- 2.20.1