From 4f1885a7b347a905cd9ed7deb6472a9688637432 Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Fri, 17 Jan 2020 18:55:22 +0530 Subject: drivers: char: ipmi: ipmi_msghandler: Pass lockdep expression to RCU lists intf->cmd_rcvrs is traversed with list_for_each_entry_rcu outside an RCU read-side critical section but under the protection of intf->cmd_rcvrs_mutex. ipmi_interfaces is traversed using list_for_each_entry_rcu outside an RCU read-side critical section but under the protection of ipmi_interfaces_mutex. Hence, add the corresponding lockdep expression to the list traversal primitive to silence false-positive lockdep warnings, and harden RCU lists. Add macro for the corresponding lockdep expression to make the code clean and concise. Signed-off-by: Amol Grover Message-Id: <20200117132521.31020-1-frextrite@gmail.com> Acked-by: Paul E. McKenney Tested-by: John Garry Signed-off-by: Corey Minyard --- drivers/char/ipmi/ipmi_msghandler.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index cad9563f8f48..64ba16dcb681 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -618,6 +618,8 @@ static DEFINE_MUTEX(ipmidriver_mutex); static LIST_HEAD(ipmi_interfaces); static DEFINE_MUTEX(ipmi_interfaces_mutex); +#define ipmi_interfaces_mutex_held() \ + lockdep_is_held(&ipmi_interfaces_mutex) static struct srcu_struct ipmi_interfaces_srcu; /* @@ -1321,7 +1323,8 @@ static void _ipmi_destroy_user(struct ipmi_user *user) * synchronize_srcu()) then free everything in that list. */ mutex_lock(&intf->cmd_rcvrs_mutex); - list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) { + list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link, + lockdep_is_held(&intf->cmd_rcvrs_mutex)) { if (rcvr->user == user) { list_del_rcu(&rcvr->link); rcvr->next = rcvrs; @@ -1599,7 +1602,8 @@ static struct cmd_rcvr *find_cmd_rcvr(struct ipmi_smi *intf, { struct cmd_rcvr *rcvr; - list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) { + list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link, + lockdep_is_held(&intf->cmd_rcvrs_mutex)) { if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd) && (rcvr->chans & (1 << chan))) return rcvr; @@ -1614,7 +1618,8 @@ static int is_cmd_rcvr_exclusive(struct ipmi_smi *intf, { struct cmd_rcvr *rcvr; - list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) { + list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link, + lockdep_is_held(&intf->cmd_rcvrs_mutex)) { if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd) && (rcvr->chans & chans)) return 0; @@ -3450,7 +3455,8 @@ int ipmi_add_smi(struct module *owner, /* Look for a hole in the numbers. */ i = 0; link = &ipmi_interfaces; - list_for_each_entry_rcu(tintf, &ipmi_interfaces, link) { + list_for_each_entry_rcu(tintf, &ipmi_interfaces, link, + ipmi_interfaces_mutex_held()) { if (tintf->intf_num != i) { link = &tintf->link; break; -- cgit v1.2.3