Re: [PATCH v5 bpf 0/4] lwt: fix return values of BPF ops

From: Yan Zhai
Date: Wed Aug 16 2023 - 11:22:16 EST

On Wed, Aug 16, 2023 at 9:27 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
>
> Hi Yan,
>
> On 8/16/23 4:54 AM, Yan Zhai wrote:
> > lwt xmit hook does not expect positive return values in function
> > ip_finish_output2 and ip6_finish_output. However, BPF programs can
> > directly return positive statuses such like NET_XMIT_DROP, NET_RX_DROP,
> > and etc to the caller. Such return values would make the kernel continue
> > processing already freed skbs and eventually panic.
> >
> > This set fixes the return values from BPF ops to unexpected continue
> > processing, and checks strictly on the correct continue condition for
> > future proof. In addition, add missing selftests for BPF_REDIRECT
> > and BPF_REROUTE cases for BPF-CI.
> >
> > v4: https://lore.kernel.org/bpf/ZMD1sFTW8SFiex+x@debian.debian/T/
> > v3: https://lore.kernel.org/bpf/cover.1690255889.git.yan@xxxxxxxxxxxxxx/
> > v2: https://lore.kernel.org/netdev/ZLdY6JkWRccunvu0@debian.debian/
> > v1: https://lore.kernel.org/bpf/ZLbYdpWC8zt9EJtq@debian.debian/
> >
> > changes since v4:
> > * fixed same error on BPF_REROUTE path
> > * re-implemented selftests under BPF-CI requirement
>
> BPF CI failed: https://github.com/kernel-patches/bpf/actions/runs/5874202507/job/15929012788
>
> Looks like due to dummy device issue. Either you might need to add this to
> the tools/testing/selftests/bpf/config* or perhaps just use veth instead for
> link_err dev.
>
It is indeed the dummy driver issue. I will update the config. Thanks
for notifying me, now I know where to look at build results.

Yan

> Error from the above link:
>
> Notice: Success: 370/3177, Skipped: 21, Failed: 2
> Error: #131 lwt_redirect
> Error: #131 lwt_redirect
> test_lwt_redirect:PASS:pthread_create 0 nsec
> Error: #131/1 lwt_redirect/lwt_redirect_normal
> Error: #131/1 lwt_redirect/lwt_redirect_normal
> test_lwt_redirect_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_redirect_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup_redirect_target:PASS:open_tuntap 0 nsec
> setup_redirect_target:PASS:if_nametoindex 0 nsec
> setup_redirect_target:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> test_lwt_redirect_normal:FAIL:setup_redirect_target unexpected setup_redirect_target: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> Error: #131/2 lwt_redirect/lwt_redirect_normal_nomac
> Error: #131/2 lwt_redirect/lwt_redirect_normal_nomac
> test_lwt_redirect_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_redirect_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup_redirect_target:PASS:open_tuntap 0 nsec
> setup_redirect_target:PASS:if_nametoindex 0 nsec
> setup_redirect_target:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> test_lwt_redirect_normal_nomac:FAIL:setup_redirect_target unexpected setup_redirect_target: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> Error: #131/3 lwt_redirect/lwt_redirect_dev_down
> Error: #131/3 lwt_redirect/lwt_redirect_dev_down
> test_lwt_redirect_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_redirect_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup_redirect_target:PASS:open_tuntap 0 nsec
> setup_redirect_target:PASS:if_nametoindex 0 nsec
> setup_redirect_target:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> __test_lwt_redirect_dev_down:FAIL:setup_redirect_target unexpected setup_redirect_target: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> Error: #131/4 lwt_redirect/lwt_redirect_dev_down_nomac
> Error: #131/4 lwt_redirect/lwt_redirect_dev_down_nomac
> test_lwt_redirect_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_redirect_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup_redirect_target:PASS:open_tuntap 0 nsec
> setup_redirect_target:PASS:if_nametoindex 0 nsec
> setup_redirect_target:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> __test_lwt_redirect_dev_down:FAIL:setup_redirect_target unexpected setup_redirect_target: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> Error: #131/5 lwt_redirect/lwt_redirect_dev_carrier_down
> Error: #131/5 lwt_redirect/lwt_redirect_dev_carrier_down
> test_lwt_redirect_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_redirect_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup_redirect_target:PASS:open_tuntap 0 nsec
> setup_redirect_target:PASS:if_nametoindex 0 nsec
> setup_redirect_target:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> test_lwt_redirect_dev_carrier_down:FAIL:setup_redirect_target unexpected setup_redirect_target: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> test_lwt_redirect:PASS:pthread_join 0 nsec
> Error: #132 lwt_reroute
> Error: #132 lwt_reroute
> test_lwt_reroute:PASS:pthread_create 0 nsec
> Error: #132/1 lwt_reroute/lwt_reroute_normal_xmit
> Error: #132/1 lwt_reroute/lwt_reroute_normal_xmit
> test_lwt_reroute_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_reroute_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup:PASS:open_tun 0 nsec
> setup:PASS:if_nametoindex 0 nsec
> setup:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> test_lwt_reroute_normal_xmit:FAIL:setup_reroute unexpected setup_reroute: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> Error: #132/2 lwt_reroute/lwt_reroute_qdisc_dropped
> Error: #132/2 lwt_reroute/lwt_reroute_qdisc_dropped
> test_lwt_reroute_run:PASS:netns_create 0 nsec
> open_netns:PASS:malloc token 0 nsec
> open_netns:PASS:open /proc/self/ns/net 0 nsec
> open_netns:PASS:open netns fd 0 nsec
> open_netns:PASS:setns 0 nsec
> test_lwt_reroute_run:PASS:setns 0 nsec
> open_tuntap:PASS:open(/dev/net/tun) 0 nsec
> open_tuntap:PASS:ioctl(TUNSETIFF) 0 nsec
> open_tuntap:PASS:fcntl(O_NONBLOCK) 0 nsec
> setup:PASS:open_tun 0 nsec
> setup:PASS:if_nametoindex 0 nsec
> setup:FAIL:ip link add link_err type dummy unexpected error: 512 (errno 0)
> test_lwt_reroute_qdisc_dropped:FAIL:setup_reroute unexpected setup_reroute: actual -1 < expected 0
> close_netns:PASS:setns 0 nsec
> test_lwt_reroute:PASS:pthread_join 0 nsec
> Test Results:
> bpftool: PASS
> test_progs: FAIL (returned 1)
> shutdown: CLEAN
> Error: Process completed with exit code 1.
>
> Thanks,
> Daniel



--

Yan