From: Jesper Dangaard Brouer <brouer@redhat.com>
Date: Thu, 8 Feb 2018 12:48:17 +0100
Subject: tools/libbpf: improve the pr_debug statements to contain section
numbers
Patch-mainline: v4.16-rc1
Git-commit: 077c066a6c5445423147496e6c9b9a2c2d2ee762
References: bsc#1109837
While debugging a bpf ELF loading issue, I needed to correlate the
ELF section number with the failed relocation section reference.
Thus, add section numbers/index to the pr_debug.
In debug mode, also print section that were skipped. This helped
me identify that a section (.eh_frame) was skipped, and this was
the reason the relocation section (.rel.eh_frame) could not find
that section number.
The section numbers corresponds to the readelf tools Section Headers [Nr].
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
tools/lib/bpf/libbpf.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -319,8 +319,8 @@ bpf_program__init(void *data, size_t siz
prog->section_name = strdup(section_name);
if (!prog->section_name) {
- pr_warning("failed to alloc name for prog under section %s\n",
- section_name);
+ pr_warning("failed to alloc name for prog under section(%d) %s\n",
+ idx, section_name);
goto errout;
}
@@ -763,29 +763,29 @@ static int bpf_object__elf_collect(struc
idx++;
if (gelf_getshdr(scn, &sh) != &sh) {
- pr_warning("failed to get section header from %s\n",
- obj->path);
+ pr_warning("failed to get section(%d) header from %s\n",
+ idx, obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
name = elf_strptr(elf, ep->e_shstrndx, sh.sh_name);
if (!name) {
- pr_warning("failed to get section name from %s\n",
- obj->path);
+ pr_warning("failed to get section(%d) name from %s\n",
+ idx, obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
data = elf_getdata(scn, 0);
if (!data) {
- pr_warning("failed to get section data from %s(%s)\n",
- name, obj->path);
+ pr_warning("failed to get section(%d) data from %s(%s)\n",
+ idx, name, obj->path);
err = -LIBBPF_ERRNO__FORMAT;
goto out;
}
- pr_debug("section %s, size %ld, link %d, flags %lx, type=%d\n",
- name, (unsigned long)data->d_size,
+ pr_debug("section(%d) %s, size %ld, link %d, flags %lx, type=%d\n",
+ idx, name, (unsigned long)data->d_size,
(int)sh.sh_link, (unsigned long)sh.sh_flags,
(int)sh.sh_type);
@@ -840,6 +840,8 @@ static int bpf_object__elf_collect(struc
obj->efile.reloc[n].shdr = sh;
obj->efile.reloc[n].data = data;
}
+ } else {
+ pr_debug("skip section(%d) %s\n", idx, name);
}
if (err)
goto out;
@@ -1119,8 +1121,7 @@ static int bpf_object__collect_reloc(str
prog = bpf_object__find_prog_by_idx(obj, idx);
if (!prog) {
- pr_warning("relocation failed: no %d section\n",
- idx);
+ pr_warning("relocation failed: no section(%d)\n", idx);
return -LIBBPF_ERRNO__RELOC;
}