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authorToke Høiland-Jørgensen <toke@redhat.com>2019-11-09 21:37:29 +0100
committerAlexei Starovoitov <ast@kernel.org>2019-11-10 19:26:30 -0800
commit4f33ddb4e3e28ade924fbf05ec8bcd7d5c022fee (patch)
treee32447f1487caabdc5d90cc29c75cd16bf5cbf14 /tools/lib
parent9c4e395a1e8c1dc14189b88f24d111f80353b9a4 (diff)
libbpf: Propagate EPERM to caller on program load
When loading an eBPF program, libbpf overrides the return code for EPERM errors instead of returning it to the caller. This makes it hard to figure out what went wrong on load. In particular, EPERM is returned when the system rlimit is too low to lock the memory required for the BPF program. Previously, this was somewhat obscured because the rlimit error would be hit on map creation (which does return it correctly). However, since maps can now be reused, object load can proceed all the way to loading programs without hitting the error; propagating it even in this case makes it possible for the caller to react appropriately (and, e.g., attempt to raise the rlimit before retrying). Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/157333184946.88376.11768171652794234561.stgit@toke.dk
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.c27
1 files changed, 11 insertions, 16 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d8ead85903d1..847b62895f9b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3721,7 +3721,7 @@ retry_load:
free(log_buf);
goto retry_load;
}
- ret = -LIBBPF_ERRNO__LOAD;
+ ret = -errno;
cp = libbpf_strerror_r(errno, errmsg, sizeof(errmsg));
pr_warn("load bpf program failed: %s\n", cp);
@@ -3734,23 +3734,18 @@ retry_load:
pr_warn("Program too large (%zu insns), at most %d insns\n",
load_attr.insns_cnt, BPF_MAXINSNS);
ret = -LIBBPF_ERRNO__PROG2BIG;
- } else {
+ } else if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
/* Wrong program type? */
- if (load_attr.prog_type != BPF_PROG_TYPE_KPROBE) {
- int fd;
-
- load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
- load_attr.expected_attach_type = 0;
- fd = bpf_load_program_xattr(&load_attr, NULL, 0);
- if (fd >= 0) {
- close(fd);
- ret = -LIBBPF_ERRNO__PROGTYPE;
- goto out;
- }
- }
+ int fd;
- if (log_buf)
- ret = -LIBBPF_ERRNO__KVER;
+ load_attr.prog_type = BPF_PROG_TYPE_KPROBE;
+ load_attr.expected_attach_type = 0;
+ fd = bpf_load_program_xattr(&load_attr, NULL, 0);
+ if (fd >= 0) {
+ close(fd);
+ ret = -LIBBPF_ERRNO__PROGTYPE;
+ goto out;
+ }
}
out: