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authorAndrei Matei <andreimatei1@gmail.com>2020-12-02 23:34:10 -0500
committerAndrii Nakryiko <andrii@kernel.org>2020-12-03 11:37:05 -0800
commit80b2b5c3a701d56de98d00d99bc9cc384fb316d9 (patch)
treede3e4fcc2771f5974b06446cb2decd09c28ebf22 /tools/lib/bpf
parenta8b415c9bde69dc194e57db8c27cb96908b30aca (diff)
libbpf: Fail early when loading programs with unspecified type
Before this patch, a program with unspecified type (BPF_PROG_TYPE_UNSPEC) would be passed to the BPF syscall, only to have the kernel reject it with an opaque invalid argument error. This patch makes libbpf reject such programs with a nicer error message - in particular libbpf now tries to diagnose bad ELF section names at both open time and load time. Signed-off-by: Andrei Matei <andreimatei1@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201203043410.59699-1-andreimatei1@gmail.com
Diffstat (limited to 'tools/lib/bpf')
-rw-r--r--tools/lib/bpf/libbpf.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 313034117070..d6f45538444d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -6629,6 +6629,16 @@ load_program(struct bpf_program *prog, struct bpf_insn *insns, int insns_cnt,
char *log_buf = NULL;
int btf_fd, ret;
+ if (prog->type == BPF_PROG_TYPE_UNSPEC) {
+ /*
+ * The program type must be set. Most likely we couldn't find a proper
+ * section definition at load time, and thus we didn't infer the type.
+ */
+ pr_warn("prog '%s': missing BPF prog type, check ELF section name '%s'\n",
+ prog->name, prog->sec_name);
+ return -EINVAL;
+ }
+
if (!insns || !insns_cnt)
return -EINVAL;
@@ -6920,9 +6930,12 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
bpf_object__for_each_program(prog, obj) {
prog->sec_def = find_sec_def(prog->sec_name);
- if (!prog->sec_def)
+ if (!prog->sec_def) {
/* couldn't guess, but user might manually specify */
+ pr_debug("prog '%s': unrecognized ELF section name '%s'\n",
+ prog->name, prog->sec_name);
continue;
+ }
if (prog->sec_def->is_sleepable)
prog->prog_flags |= BPF_F_SLEEPABLE;