Messages in this thread Patch in this message | | | From | Amol Grover <> | Subject | [PATCH v2] drivers: char: ipmi: ipmi_msghandler: Pass lockdep expression to RCU lists | Date | Fri, 10 Jan 2020 22:17:10 +0530 |
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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 <frextrite@gmail.com> --- v2: - Fix sparse error CHECK: Alignment should match open parenthesis
drivers/char/ipmi/ipmi_msghandler.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c index cad9563f8f48..1cbeacb1e8b9 100644 --- a/drivers/char/ipmi/ipmi_msghandler.c +++ b/drivers/char/ipmi/ipmi_msghandler.c @@ -35,6 +35,8 @@ #include <linux/nospec.h> #define IPMI_DRIVER_VERSION "39.2" +#define cmd_rcvrs_mutex_held() \ + lockdep_is_held(&intf->cmd_rcvrs_mutex) static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void); static int ipmi_init_msghandler(void); @@ -618,6 +620,8 @@ 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 +1325,8 @@ 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, + cmd_rcvrs_mutex_held()) { if (rcvr->user == user) { list_del_rcu(&rcvr->link); rcvr->next = rcvrs; @@ -1599,7 +1604,8 @@ 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, + rcu_read_lock_held() || cmd_rcvrs_mutex_held()) { if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd) && (rcvr->chans & (1 << chan))) return rcvr; @@ -1614,7 +1620,8 @@ 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, + cmd_rcvrs_mutex_held()) { if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd) && (rcvr->chans & chans)) return 0; @@ -3450,7 +3457,8 @@ 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; -- 2.24.1
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