mac80211: Fix sleeping allocation under lock in mesh_path_node_copy.

The mesh_path_node_copy() can be called like this:
mesh_path_add
 `- write_lock(&pathtbl_resize_lock); /* ! */
 `- mesh_table_grow
     `- ->copy_node
           `- mesh_path_node_copy

thus, the GFP_KERNEL is not suitable here.

The acceptable fix, I suppose, is make this allocation GPF_ATOMIC -
the mpath_node being allocated is 4 pointers, i.e. this allocation
is small enough to survive even under a moderate memory pressure.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c
index fe1ceee..1154398 100644 (file)
--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -469,7 +469,7 @@ static int mesh_path_node_copy(struct hlist_node *p, struct mesh_table *newtbl)
        struct mpath_node *node, *new_node;
        u32 hash_idx;
 
-       new_node = kmalloc(sizeof(struct mpath_node), GFP_KERNEL);
+       new_node = kmalloc(sizeof(struct mpath_node), GFP_ATOMIC);
        if (new_node == NULL)
                return -ENOMEM;