[PATCH bpf-next v4 1/2] bpf, xdp: Add tracepoint to xdp attaching failure
From: Leon Hwang <hidden>
Date: 2023-07-30 11:50:17
Also in:
bpf, linux-kselftest, lkml, netdev
Subsystem:
bpf [general] (safe dynamic programs and tools), networking [general], the rest, tracing, xdp (express data path) · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu, David S. Miller, Jesper Dangaard Brouer, John Fastabend
When error happens in dev_xdp_attach(), it should have a way to tell users the error message like the netlink approach. To avoid breaking uapi, adding a tracepoint in bpf_xdp_link_attach() is an appropriate way to notify users the error message. Hence, bpf libraries are able to retrieve the error message by this tracepoint, and then report the error message to users. Signed-off-by: Leon Hwang <redacted> --- include/trace/events/xdp.h | 17 +++++++++++++++++ net/core/dev.c | 5 ++++- 2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h
index c40fc97f94171..cd89f1d5ce7b8 100644
--- a/include/trace/events/xdp.h
+++ b/include/trace/events/xdp.h@@ -404,6 +404,23 @@ TRACE_EVENT(mem_return_failed, ) ); +TRACE_EVENT(bpf_xdp_link_attach_failed, + + TP_PROTO(const char *msg), + + TP_ARGS(msg), + + TP_STRUCT__entry( + __string(msg, msg) + ), + + TP_fast_assign( + __assign_str(msg, msg); + ), + + TP_printk("errmsg=%s", __get_str(msg)) +); + #endif /* _TRACE_XDP_H */ #include <trace/define_trace.h>
diff --git a/net/core/dev.c b/net/core/dev.c
index 8e7d0cb540cdb..49bed890f807e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -133,6 +133,7 @@ #include <trace/events/net.h> #include <trace/events/skb.h> #include <trace/events/qdisc.h> +#include <trace/events/xdp.h> #include <linux/inetdevice.h> #include <linux/cpu_rmap.h> #include <linux/static_key.h>
@@ -9472,6 +9473,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) struct bpf_link_primer link_primer; struct bpf_xdp_link *link; struct net_device *dev; + struct netlink_ext_ack extack; int err, fd; rtnl_lock();
@@ -9497,12 +9499,13 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) goto unlock; } - err = dev_xdp_attach_link(dev, NULL, link); + err = dev_xdp_attach_link(dev, &extack, link); rtnl_unlock(); if (err) { link->dev = NULL; bpf_link_cleanup(&link_primer); + trace_bpf_xdp_link_attach_failed(extack._msg); goto out_put_dev; }
--
2.41.0