| Message ID | 1609892546-11389-1-git-send-email-stranche@quicinc.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,1/2] net: ipv6: fib: flush exceptions when purging route | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | fail | Series targets non-next tree, but doesn't contain any Fixes tags |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 2 maintainers not CCed: kuznet@ms2.inr.ac.ru yoshfuji@linux-ipv6.org |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 1 this patch: 1 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 17 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 1 this patch: 1 |
| netdev/header_inline | success | Link |
| netdev/stable | success | Stable not CCed |
On 1/5/21 5:22 PM, Sean Tranchetti wrote: > From: Sean Tranchetti <stranche@codeaurora.org> > > Route removal is handled by two code paths. The main removal path is via > fib6_del_route() which will handle purging any PMTU exceptions from the > cache, removing all per-cpu copies of the DST entry used by the route, and > releasing the fib6_info struct. > > The second removal location is during fib6_add_rt2node() during a route > replacement operation. This path also calls fib6_purge_rt() to handle > cleaning up the per-cpu copies of the DST entries and releasing the > fib6_info associated with the older route, but it does not flush any PMTU > exceptions that the older route had. Since the older route is removed from > the tree during the replacement, we lose any way of accessing it again. > > As these lingering DSTs and the fib6_info struct are holding references to > the underlying netdevice struct as well, unregistering that device from the > kernel can never complete. > I think the right fixes tag is: Fixes: 2b760fcf5cfb3 ("ipv6: hook up exception table to store dst cache") cc'ed author of that patch. > Signed-off-by: Sean Tranchetti <stranche@codeaurora.org> > --- > net/ipv6/ip6_fib.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c > index 605cdd3..f43e275 100644 > --- a/net/ipv6/ip6_fib.c > +++ b/net/ipv6/ip6_fib.c > @@ -1025,6 +1025,8 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, > { > struct fib6_table *table = rt->fib6_table; > > + /* Flush all cached dst in exception table */ > + rt6_flush_exceptions(rt); > fib6_drop_pcpu_from(rt, table); > > if (rt->nh && !list_empty(&rt->nh_list)) > @@ -1927,9 +1929,6 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, > net->ipv6.rt6_stats->fib_rt_entries--; > net->ipv6.rt6_stats->fib_discarded_routes++; > > - /* Flush all cached dst in exception table */ > - rt6_flush_exceptions(rt); > - > /* Reset round-robin state, if necessary */ > if (rcu_access_pointer(fn->rr_ptr) == rt) > fn->rr_ptr = NULL; > Reviewed-by: David Ahern <dsahern@kernel.org>
On Wed, 6 Jan 2021 09:55:09 -0700 David Ahern wrote: > On 1/5/21 5:22 PM, Sean Tranchetti wrote: > > From: Sean Tranchetti <stranche@codeaurora.org> > > > > Route removal is handled by two code paths. The main removal path is via > > fib6_del_route() which will handle purging any PMTU exceptions from the > > cache, removing all per-cpu copies of the DST entry used by the route, and > > releasing the fib6_info struct. > > > > The second removal location is during fib6_add_rt2node() during a route > > replacement operation. This path also calls fib6_purge_rt() to handle > > cleaning up the per-cpu copies of the DST entries and releasing the > > fib6_info associated with the older route, but it does not flush any PMTU > > exceptions that the older route had. Since the older route is removed from > > the tree during the replacement, we lose any way of accessing it again. > > > > As these lingering DSTs and the fib6_info struct are holding references to > > the underlying netdevice struct as well, unregistering that device from the > > kernel can never complete. > > I think the right fixes tag is: > > Fixes: 2b760fcf5cfb3 ("ipv6: hook up exception table to store dst cache") > > cc'ed author of that patch. > > > Signed-off-by: Sean Tranchetti <stranche@codeaurora.org> > > Reviewed-by: David Ahern <dsahern@kernel.org> Applied, thanks!
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 605cdd3..f43e275 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1025,6 +1025,8 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, { struct fib6_table *table = rt->fib6_table; + /* Flush all cached dst in exception table */ + rt6_flush_exceptions(rt); fib6_drop_pcpu_from(rt, table); if (rt->nh && !list_empty(&rt->nh_list)) @@ -1927,9 +1929,6 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn, net->ipv6.rt6_stats->fib_rt_entries--; net->ipv6.rt6_stats->fib_discarded_routes++; - /* Flush all cached dst in exception table */ - rt6_flush_exceptions(rt); - /* Reset round-robin state, if necessary */ if (rcu_access_pointer(fn->rr_ptr) == rt) fn->rr_ptr = NULL;