From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-px0-f170.google.com ([209.85.212.170]:51390 "EHLO mail-px0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753938Ab1ECX5n (ORCPT ); Tue, 3 May 2011 19:57:43 -0400 Received: by mail-px0-f170.google.com with SMTP id 19so426563pxi.1 for ; Tue, 03 May 2011 16:57:43 -0700 (PDT) From: Javier Cardona To: "John W. Linville" Cc: Javier Cardona , Thomas Pedersen , devel@lists.open80211s.org, Johannes Berg , linux-wireless@vger.kernel.org, jlopex@gmail.com Subject: [PATCH 09/13] Check size of a new mesh path table for changes since allocation. Date: Tue, 3 May 2011 16:57:15 -0700 Message-Id: <1304467039-7730-10-git-send-email-javier@cozybit.com> (sfid-20110504_015749_589118_CB6CF68F) In-Reply-To: <1304467039-7730-1-git-send-email-javier@cozybit.com> References: <1304467039-7730-1-git-send-email-javier@cozybit.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- net/mac80211/mesh_pathtbl.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mac80211/mesh_pathtbl.c b/net/mac80211/mesh_pathtbl.c index 35c715a..d4e86fd 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); -- 1.7.1