Commit df7274eb authored Aug 09, 2016 by Florian Westphal Committed by Steffen Klassert Aug 10, 2016

xfrm: state: delay freeing until rcu grace period has elapsed



The hash table backend memory and the state structs are free'd via
kfree/vfree.

Once we only rely on rcu during lookups we have to make sure no other cpu
is currently accessing this before doing the free.

Free operations already happen from worker so we can use synchronize_rcu
to wait until concurrent readers are done.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

parent 02efdff7

net/xfrm/xfrm_state.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -146,6 +146,9 @@ static void xfrm_hash_resize(struct work_struct *work)
		spin_unlock_bh(&net->xfrm.xfrm_state_lock);

		osize = (ohashmask + 1) * sizeof(struct hlist_head);

		synchronize_rcu();

		xfrm_hash_free(odst, osize);
		xfrm_hash_free(osrc, osize);
		xfrm_hash_free(ospi, osize);
		@@ -369,6 +372,8 @@ static void xfrm_state_gc_task(struct work_struct *work)
		hlist_move_list(&net->xfrm.state_gc_list, &gc_list);
		spin_unlock_bh(&xfrm_state_gc_lock);

		synchronize_rcu();

		hlist_for_each_entry_safe(x, tmp, &gc_list, gclist)
		xfrm_state_gc_destroy(x);
		}