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mac80211: Check size of a new mesh path table for changes since allocation.

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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 <javier@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Javier Cardona
2011-05-03 16:57:15 -07:00
committed by John W. Linville
parent 8f9cb77d6d
commit 9ca99eeca0
1 changed files with 6 additions and 3 deletions
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9
net/mac80211/mesh_pathtbl.c
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@@ -76,7 +76,6 @@ static int mesh_table_grow(struct mesh_table *oldtbl,
< oldtbl->mean_chain_len * (oldtbl->hash_mask + 1)) < oldtbl->mean_chain_len * (oldtbl->hash_mask + 1))
return -EAGAIN; return -EAGAIN;
newtbl->free_node = oldtbl->free_node; newtbl->free_node = oldtbl->free_node;
newtbl->mean_chain_len = oldtbl->mean_chain_len; newtbl->mean_chain_len = oldtbl->mean_chain_len;
newtbl->copy_node = oldtbl->copy_node; newtbl->copy_node = oldtbl->copy_node;
@@ -329,7 +328,8 @@ void mesh_mpath_table_grow(void)
{ {
struct mesh_table *oldtbl, *newtbl; 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) if (!newtbl)
return; return;
write_lock(&pathtbl_resize_lock); write_lock(&pathtbl_resize_lock);
@@ -339,6 +339,7 @@ void mesh_mpath_table_grow(void)
write_unlock(&pathtbl_resize_lock); write_unlock(&pathtbl_resize_lock);
return; return;
} }
rcu_read_unlock();
rcu_assign_pointer(mesh_paths, newtbl); rcu_assign_pointer(mesh_paths, newtbl);
write_unlock(&pathtbl_resize_lock); write_unlock(&pathtbl_resize_lock);
@@ -350,7 +351,8 @@ void mesh_mpp_table_grow(void)
{ {
struct mesh_table *oldtbl, *newtbl; 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) if (!newtbl)
return; return;
write_lock(&pathtbl_resize_lock); write_lock(&pathtbl_resize_lock);
@@ -360,6 +362,7 @@ void mesh_mpp_table_grow(void)
write_unlock(&pathtbl_resize_lock); write_unlock(&pathtbl_resize_lock);
return; return;
} }
rcu_read_unlock();
rcu_assign_pointer(mpp_paths, newtbl); rcu_assign_pointer(mpp_paths, newtbl);
write_unlock(&pathtbl_resize_lock); write_unlock(&pathtbl_resize_lock);