On Thu, 25 Aug 2011 11:16:50 -0700, Javier Cardona wrote:
On Wed, Aug 24, 2011 at 7:08 PM, Johannes Berg
<johannes@xxxxxxxxxxxxxxxx> wrote:
On Wed, 24 Aug 2011 18:40:44 -0700, Thomas Pedersen wrote:
da = hdr->addr3;
ra = hdr->addr1;
+ rcu_read_lock();
mpath = mesh_path_lookup(da, sdata);
+ rcu_read_unlock();
if (mpath)
sn = ++mpath->sn;
mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
skb->data,
You've got to be kidding. Didn't I just explain RCU :)
The patch was prepared before your RCU session :(
Just to confirm I got it right before we resubmit: given that not
only
the path table accessed inside mesh_path_lookup() but also the mpaths
themselves are RCU protected, the right fix should have been
da = hdr->addr3;
ra = hdr->addr1;
+ rcu_read_lock();
mpath = mesh_path_lookup(da, sdata);
if (mpath)
sn = ++mpath->sn;
+ rcu_read_unlock();
mesh_path_error_tx(sdata->u.mesh.mshcfg.element_ttl,
skb->data,
Correct?
Frankly, I'm not sure, since you modify the mpath->sn you probably need
to hold a real lock, otherwise ++mpath->sn can race against itself in
this very function.
johannes
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