Re: [PATCH v4 bpf-next 07/12] libbpf: add BPF static linker BTF and BTF.ext support
From: Andrii Nakryiko <hidden>
Date: 2021-03-28 18:30:26
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netdev
On Sun, Mar 28, 2021 at 5:03 AM Jiri Olsa [off-list ref] wrote:
On Fri, Mar 19, 2021 at 07:58:13PM +0100, Jiri Olsa wrote:quoted
On Fri, Mar 19, 2021 at 11:39:01AM -0700, Andrii Nakryiko wrote:quoted
On Fri, Mar 19, 2021 at 9:23 AM Jiri Olsa [off-list ref] wrote:quoted
On Thu, Mar 18, 2021 at 12:40:31PM -0700, Andrii Nakryiko wrote: SNIPquoted
+ + return NULL; +} + +static int linker_fixup_btf(struct src_obj *obj) +{ + const char *sec_name; + struct src_sec *sec; + int i, j, n, m; + + n = btf__get_nr_types(obj->btf);hi, I'm getting bpftool crash when building tests, looks like above obj->btf can be NULL:I lost if (!obj->btf) return 0; somewhere along the rebases. I'll send a fix shortly. But how did you end up with selftests BPF objects built without BTF?no idea.. I haven't even updated llvm for almost 3 days now ;-)sorry for late follow up on this, and it's actually forgotten empty object in progs directory that was causing this I wonder we should add empty object like below to catch these cases,
well, feel free to chime in on [0] then [0] https://patchwork.kernel.org/project/netdevbpf/patch/20210319205909.1748642-4-andrii@kernel.org/
because there's another place that bpftool is crashing on with it I can send full patch for that if you think it's worth having
sure, but see my comment below
quoted hunk ↗ jump to hunk
jirka ---diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7aad78dbb4b4..aecb6ca52bce 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c@@ -3165,6 +3165,9 @@ static int add_dummy_ksym_var(struct btf *btf) const struct btf_var_secinfo *vs; const struct btf_type *sec; + if (!btf) + return 0; +
add_dummy_ksym_var() shouldn't be called, if there is no btf, so the fix should be outside of this fix.
quoted hunk ↗ jump to hunk
sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC, BTF_KIND_DATASEC); if (sec_btf_id < 0)diff --git a/tools/testing/selftests/bpf/progs/empty.c b/tools/testing/selftests/bpf/progs/empty.c new file mode 100644 index 000000000000..e69de29bb2d1