| Message ID | 20190223063434.6793-2-joel@joelfernandes.org |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
| Series | RCU fixes for rcu_assign_pointer() usage | expand |
On Sat, Feb 23, 2019 at 01:34:29AM -0500, Joel Fernandes (Google) wrote: > rtnl_register_internal() and rtnl_unregister_all tries to directly > dereference an RCU protected pointed outside RCU read side section. > While this is Ok to do since a lock is held, let us use the correct > API to avoid programmer bugs in the future. > > This also fixes sparse warnings arising from not using RCU API. > > net/core/rtnetlink.c:332:13: warning: incorrect type in assignment > (different address spaces) net/core/rtnetlink.c:332:13: expected > struct rtnl_link **tab net/core/rtnetlink.c:332:13: got struct > rtnl_link *[noderef] <asn:4>*<noident> > > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> From an RCU perspective: Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com> > --- > net/core/rtnetlink.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 5ea1bed08ede..98be4b4818a9 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -188,7 +188,7 @@ static int rtnl_register_internal(struct module *owner, > msgindex = rtm_msgindex(msgtype); > > rtnl_lock(); > - tab = rtnl_msg_handlers[protocol]; > + tab = rtnl_dereference(rtnl_msg_handlers[protocol]); > if (tab == NULL) { > tab = kcalloc(RTM_NR_MSGTYPES, sizeof(void *), GFP_KERNEL); > if (!tab) > @@ -329,7 +329,7 @@ void rtnl_unregister_all(int protocol) > BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); > > rtnl_lock(); > - tab = rtnl_msg_handlers[protocol]; > + tab = rtnl_dereference(rtnl_msg_handlers[protocol]); > if (!tab) { > rtnl_unlock(); > return; > -- > 2.21.0.rc0.258.g878e2cd30e-goog >
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 5ea1bed08ede..98be4b4818a9 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -188,7 +188,7 @@ static int rtnl_register_internal(struct module *owner, msgindex = rtm_msgindex(msgtype); rtnl_lock(); - tab = rtnl_msg_handlers[protocol]; + tab = rtnl_dereference(rtnl_msg_handlers[protocol]); if (tab == NULL) { tab = kcalloc(RTM_NR_MSGTYPES, sizeof(void *), GFP_KERNEL); if (!tab) @@ -329,7 +329,7 @@ void rtnl_unregister_all(int protocol) BUG_ON(protocol < 0 || protocol > RTNL_FAMILY_MAX); rtnl_lock(); - tab = rtnl_msg_handlers[protocol]; + tab = rtnl_dereference(rtnl_msg_handlers[protocol]); if (!tab) { rtnl_unlock(); return;
rtnl_register_internal() and rtnl_unregister_all tries to directly dereference an RCU protected pointed outside RCU read side section. While this is Ok to do since a lock is held, let us use the correct API to avoid programmer bugs in the future. This also fixes sparse warnings arising from not using RCU API. net/core/rtnetlink.c:332:13: warning: incorrect type in assignment (different address spaces) net/core/rtnetlink.c:332:13: expected struct rtnl_link **tab net/core/rtnetlink.c:332:13: got struct rtnl_link *[noderef] <asn:4>*<noident> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> --- net/core/rtnetlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)