| Message ID | 20220207171319.157775-1-atenart@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | net: fix issues when uncloning an skb dst+metadata | expand |
Hello: This series was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Mon, 7 Feb 2022 18:13:17 +0100 you wrote: > Hi, > > This fixes two issues when uncloning an skb dst+metadata in > tun_dst_unclone; this was initially reported by Vlad Buslov[1]. Because > of the memory leak fixed by patch 2, the issue in patch 1 never happened > in practice. > > [...] Here is the summary with links: - [net,v2,1/2] net: do not keep the dst cache when uncloning an skb dst and its metadata https://git.kernel.org/netdev/net/c/cfc56f85e72f - [net,v2,2/2] net: fix a memleak when uncloning an skb dst and its metadata https://git.kernel.org/netdev/net/c/9eeabdf17fa0 You are awesome, thank you!
Hi, This fixes two issues when uncloning an skb dst+metadata in tun_dst_unclone; this was initially reported by Vlad Buslov[1]. Because of the memory leak fixed by patch 2, the issue in patch 1 never happened in practice. tun_dst_unclone is called from two different places, one in geneve/vxlan to handle PMTU and one in net/openvswitch/actions.c where it is used to retrieve tunnel information. While both Vlad and I tested the former, we could not for the latter. I did spend quite some time trying to, but that code path is not easy to trigger. Code inspection shows this should be fine, the tunnel information (dst+metadata) is uncloned and the skb it is referenced from is only consumed after all accesses to the tunnel information are done: do_execute_actions output_userspace dev_fill_metadata_dst <- dst+metadata is uncloned ovs_dp_upcall queue_userspace_packet ovs_nla_put_tunnel_info <- metadata (tunnel info) is accessed consume_skb <- dst+metadata is freed Since v1: - Only allocate a dst cache if there is one already. - Use metadata_dst_free in the dst_cache_init error path. This is OK as the dst_cache is zeroed on error. - Protect the ret variable definition with CONFIG_DST_CACHE. - Kept Vlad's Tested-by as the changes are minor. Thanks! Antoine Antoine Tenart (2): net: do not keep the dst cache when uncloning an skb dst and its metadata net: fix a memleak when uncloning an skb dst and its metadata include/net/dst_metadata.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)