Re: [PATCH] netlink: Deal with ESRCH error in nlmsg_notify()
From: Yonghong Song <hidden>
Date: 2021-07-19 14:47:31
Also in:
lkml
On 7/18/21 10:18 PM, Yajun Deng wrote:
Yonghong Song report:
The bpf selftest tc_bpf failed with latest bpf-next.
The following is the command to run and the result:
$ ./test_progs -n 132
[ 40.947571] bpf_testmod: loading out-of-tree module taints kernel.
test_tc_bpf:PASS:test_tc_bpf__open_and_load 0 nsec
test_tc_bpf:PASS:bpf_tc_hook_create(BPF_TC_INGRESS) 0 nsec
test_tc_bpf:PASS:bpf_tc_hook_create invalid hook.attach_point 0 nsec
test_tc_bpf_basic:PASS:bpf_obj_get_info_by_fd 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_attach 0 nsec
test_tc_bpf_basic:PASS:handle set 0 nsec
test_tc_bpf_basic:PASS:priority set 0 nsec
test_tc_bpf_basic:PASS:prog_id set 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_attach replace mode 0 nsec
test_tc_bpf_basic:PASS:bpf_tc_query 0 nsec
test_tc_bpf_basic:PASS:handle set 0 nsec
test_tc_bpf_basic:PASS:priority set 0 nsec
test_tc_bpf_basic:PASS:prog_id set 0 nsec
libbpf: Kernel error message: Failed to send filter delete notification
test_tc_bpf_basic:FAIL:bpf_tc_detach unexpected error: -3 (errno 3)
test_tc_bpf:FAIL:test_tc_internal ingress unexpected error: -3 (errno 3)
The failure seems due to the commit
cfdf0d9ae75b ("rtnetlink: use nlmsg_notify() in rtnetlink_send()")
Deal with ESRCH error in nlmsg_notify() even the report variable is zero.
Reported-by: Yonghong Song <redacted>
Signed-off-by: Yajun Deng <redacted>Thanks for quick fix. This does fix the bpf selftest issu. But does this change have negative impacts on other nlmsg_notify() callers, below 1-3 items? 0 net/core/rtnetlink.c rtnetlink_send 714 return nlmsg_notify(rtnl, skb, pid, group, echo, GFP_KERNEL); 1 net/core/rtnetlink.c rtnl_notify 734 nlmsg_notify(rtnl, skb, pid, group, report, flags); 2 net/netfilter/nfnetlink.c nfnetlink_send 176 return nlmsg_notify(nfnlnet->nfnl, skb, portid, group, echo, flags); 3 net/netlink/genetlink.c genl_notify 1506 nlmsg_notify(sk, skb, info->snd_portid, group, report, flags);
quoted hunk ↗ jump to hunk
--- net/netlink/af_netlink.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 380f95aacdec..24b7cf447bc5 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c@@ -2545,13 +2545,15 @@ int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid, /* errors reported via destination sk->sk_err, but propagate * delivery errors if NETLINK_BROADCAST_ERROR flag is set */ err = nlmsg_multicast(sk, skb, exclude_portid, group, flags); + if (err == -ESRCH) + err = 0; } if (report) { int err2; err2 = nlmsg_unicast(sk, skb, portid); - if (!err || err == -ESRCH) + if (!err) err = err2; }