From 9ca99eeca0cfe839c481f3350988e9ed94188567 Mon Sep 17 00:00:00 2001 From: Javier Cardona Date: Tue, 3 May 2011 16:57:15 -0700 Subject: [PATCH] mac80211: Check size of a new mesh path table for changes since allocation. Not sure if I'm chasing a ghost here, seems like the mesh_path->size_order needs to be inside an RCU-read section to prevent that value from changing between table allocation and copying. We have observed crashes that might be caused by this. Signed-off-by: Javier Cardona Signed-off-by: John W. Linville --- net/mac80211/mesh_pathtbl.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index 7776ae5a8f15..c1a2bf2aa2de 100644 --- a/net/mac80211/mesh_pathtbl.c +++ b/net/mac80211/mesh_pathtbl.c @@ -76,7 +76,6 @@ static int mesh_table_grow(struct mesh_table *oldtbl, < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1)) return -EAGAIN; - newtbl->free_node = oldtbl->free_node; newtbl->mean_chain_len = oldtbl->mean_chain_len; newtbl->copy_node = oldtbl->copy_node; @@ -329,7 +328,8 @@ void mesh_mpath_table_grow(void) { struct mesh_table *oldtbl, *newtbl; - newtbl = mesh_table_alloc(mesh_paths->size_order + 1); + rcu_read_lock(); + newtbl = mesh_table_alloc(rcu_dereference(mesh_paths)->size_order + 1); if (!newtbl) return; write_lock(&pathtbl_resize_lock); @@ -339,6 +339,7 @@ void mesh_mpath_table_grow(void) write_unlock(&pathtbl_resize_lock); return; } + rcu_read_unlock(); rcu_assign_pointer(mesh_paths, newtbl); write_unlock(&pathtbl_resize_lock); @@ -350,7 +351,8 @@ void mesh_mpp_table_grow(void) { struct mesh_table *oldtbl, *newtbl; - newtbl = mesh_table_alloc(mpp_paths->size_order + 1); + rcu_read_lock(); + newtbl = mesh_table_alloc(rcu_dereference(mpp_paths)->size_order + 1); if (!newtbl) return; write_lock(&pathtbl_resize_lock); @@ -360,6 +362,7 @@ void mesh_mpp_table_grow(void) write_unlock(&pathtbl_resize_lock); return; } + rcu_read_unlock(); rcu_assign_pointer(mpp_paths, newtbl); write_unlock(&pathtbl_resize_lock); -- 2.34.1