| Message ID | 20171011180324.15638-1-fw@strlen.de |
|---|---|
| State | Not Applicable |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | [nf] netfilter: x_tables: ensure readers see new ->private value | expand |
On Wed, Oct 11, 2017 at 11:03 AM, Florian Westphal <fw@strlen.de> wrote: > Eric Dumazet wrote: > But it seems we need an extra smp_wmb() after > smp_wmb(); > table->private = newinfo; > > Otherwise we have no guarantee other cpus actually see the new > ->private value. > > Suggested-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Florian Westphal <fw@strlen.de> I do not believe this change is needed in net (or nf) tree. See my other reply. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index d8571f414208..64cf669ecd6c 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -1182,6 +1182,9 @@ xt_replace_table(struct xt_table *table, smp_wmb(); table->private = newinfo; + /* Ensure other cpus see the new ->private value. */ + smp_wmb(); + /* * Even though table entries have now been swapped, other CPU's * may still be using the old entries. This is okay, because
Eric Dumazet wrote: But it seems we need an extra smp_wmb() after smp_wmb(); table->private = newinfo; Otherwise we have no guarantee other cpus actually see the new ->private value. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> --- net/netfilter/x_tables.c | 3 +++ 1 file changed, 3 insertions(+)