diff options
| -rw-r--r-- | include/trace/events/xdp.h | 17 | ||||
| -rw-r--r-- | net/core/dev.c | 5 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/xdp_attach.c | 65 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c | 54 |
4 files changed, 140 insertions, 1 deletions
diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h index c40fc97f9417..cd89f1d5ce7b 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 8e7d0cb540cd..002fec07de73 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> @@ -9470,6 +9471,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) { struct net *net = current->nsproxy->net_ns; struct bpf_link_primer link_primer; + struct netlink_ext_ack extack = {}; struct bpf_xdp_link *link; struct net_device *dev; int err, fd; @@ -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; } diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c index fa3cac5488f5..e6bcb6051402 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_attach.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_attach.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <test_progs.h> +#include "test_xdp_attach_fail.skel.h" #define IFINDEX_LO 1 #define XDP_FLAGS_REPLACE (1U << 4) @@ -85,10 +86,74 @@ out_1: bpf_object__close(obj1); } +#define ERRMSG_LEN 64 + +struct xdp_errmsg { + char msg[ERRMSG_LEN]; +}; + +static void on_xdp_errmsg(void *ctx, int cpu, void *data, __u32 size) +{ + struct xdp_errmsg *ctx_errmg = ctx, *tp_errmsg = data; + + memcpy(&ctx_errmg->msg, &tp_errmsg->msg, ERRMSG_LEN); +} + +static const char tgt_errmsg[] = "Invalid XDP flags for BPF link attachment"; + +static void test_xdp_attach_fail(const char *file) +{ + struct test_xdp_attach_fail *skel = NULL; + struct xdp_errmsg errmsg = {}; + struct perf_buffer *pb = NULL; + struct bpf_object *obj = NULL; + int err, fd_xdp; + + LIBBPF_OPTS(bpf_link_create_opts, opts); + + skel = test_xdp_attach_fail__open_and_load(); + if (!ASSERT_OK_PTR(skel, "test_xdp_attach_fail__open_and_load")) + goto out_close; + + err = test_xdp_attach_fail__attach(skel); + if (!ASSERT_EQ(err, 0, "test_xdp_attach_fail__attach")) + goto out_close; + + /* set up perf buffer */ + pb = perf_buffer__new(bpf_map__fd(skel->maps.xdp_errmsg_pb), 1, + on_xdp_errmsg, NULL, &errmsg, NULL); + if (!ASSERT_OK_PTR(pb, "perf_buffer__new")) + goto out_close; + + err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &fd_xdp); + if (!ASSERT_EQ(err, 0, "bpf_prog_test_load")) + goto out_close; + + opts.flags = 0xFF; // invalid flags to fail to attach XDP prog + err = bpf_link_create(fd_xdp, IFINDEX_LO, BPF_XDP, &opts); + if (!ASSERT_EQ(err, -EINVAL, "bpf_link_create")) + goto out_close; + + /* read perf buffer */ + err = perf_buffer__poll(pb, 100); + if (!ASSERT_GT(err, -1, "perf_buffer__poll")) + goto out_close; + + ASSERT_STRNEQ((const char *) errmsg.msg, tgt_errmsg, + 42 /* strlen(tgt_errmsg) */, "check error message"); + +out_close: + perf_buffer__free(pb); + bpf_object__close(obj); + test_xdp_attach_fail__destroy(skel); +} + void serial_test_xdp_attach(void) { if (test__start_subtest("xdp_attach")) test_xdp_attach("./test_xdp.bpf.o"); if (test__start_subtest("xdp_attach_dynptr")) test_xdp_attach("./test_xdp_dynptr.bpf.o"); + if (test__start_subtest("xdp_attach_failed")) + test_xdp_attach_fail("./xdp_dummy.bpf.o"); } diff --git a/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c new file mode 100644 index 000000000000..2ff1b596e87e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_xdp_attach_fail.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright Leon Hwang */ + +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +#define ERRMSG_LEN 64 + +struct xdp_errmsg { + char msg[ERRMSG_LEN]; +}; + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __type(key, int); + __type(value, int); +} xdp_errmsg_pb SEC(".maps"); + +struct xdp_attach_error_ctx { + unsigned long unused; + + /* + * bpf does not support tracepoint __data_loc directly. + * + * Actually, this field is a 32 bit integer whose value encodes + * information on where to find the actual data. The first 2 bytes is + * the size of the data. The last 2 bytes is the offset from the start + * of the tracepoint struct where the data begins. + * -- https://github.com/iovisor/bpftrace/pull/1542 + */ + __u32 msg; // __data_loc char[] msg; +}; + +/* + * Catch the error message at the tracepoint. + */ + +SEC("tp/xdp/bpf_xdp_link_attach_failed") +int tp__xdp__bpf_xdp_link_attach_failed(struct xdp_attach_error_ctx *ctx) +{ + char *msg = (void *)(__u64) ((void *) ctx + (__u16) ctx->msg); + struct xdp_errmsg errmsg = {}; + + bpf_probe_read_kernel_str(&errmsg.msg, ERRMSG_LEN, msg); + bpf_perf_event_output(ctx, &xdp_errmsg_pb, BPF_F_CURRENT_CPU, &errmsg, + ERRMSG_LEN); + return 0; +} + +/* + * Reuse the XDP program in xdp_dummy.c. + */ + +char LICENSE[] SEC("license") = "GPL"; |