On Wed, Oct 09, 2013 at 02:29:38PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" <paul...@linux.vnet.ibm.com> > > The sparse checking for rcu_assign_pointer() was recently upgraded > to reject non-__kernel address spaces. This also rejects __rcu, > which is almost always the right thing to do. However, the use in > dn_insert_route() is legitimate: It is assigning a pointer to an element
Nit: "uses ... are", not "use ... is". :) > from an RCU-protected list, and all elements of this list are already > visible to caller. > > This commit therefore silences this false positive by laundering the > pointer using rcu_access_pointer() as suggested by Josh Triplett. > > Reported-by: kbuild test robot <fengguang...@intel.com> > Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com> > Cc: "David S. Miller" <da...@davemloft.net> > Cc: Thomas Graf <tg...@suug.ch> > Cc: Gao feng <gaof...@cn.fujitsu.com> > Cc: Stephen Hemminger <shemmin...@vyatta.com> > Cc: linux-decnet-u...@lists.sourceforge.net > Cc: net...@vger.kernel.org With or without the above typo fix: Reviewed-by: Josh Triplett <j...@joshtriplett.org> > --- > net/decnet/dn_route.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c > index fe32388ea24f..3b1357bcfc92 100644 > --- a/net/decnet/dn_route.c > +++ b/net/decnet/dn_route.c > @@ -345,7 +345,7 @@ static int dn_insert_route(struct dn_route *rt, unsigned > int hash, struct dn_rou > /* Put it first */ > *rthp = rth->dst.dn_next; > rcu_assign_pointer(rth->dst.dn_next, > - dn_rt_hash_table[hash].chain); > + > rcu_access_pointer(dn_rt_hash_table[hash].chain)); > rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth); > > dst_use(&rth->dst, now); > @@ -358,7 +358,8 @@ static int dn_insert_route(struct dn_route *rt, unsigned > int hash, struct dn_rou > rthp = &rth->dst.dn_next; > } > > - rcu_assign_pointer(rt->dst.dn_next, dn_rt_hash_table[hash].chain); > + rcu_assign_pointer(rt->dst.dn_next, > + rcu_access_pointer(dn_rt_hash_table[hash].chain)); > rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt); > > dst_use(&rt->dst, now); > -- > 1.8.1.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
