On 7/25/21 10:22 PM, Hengqi Chen wrote:
On 2021/7/26 12:56 PM, Yonghong Song wrote:
On 7/25/21 9:41 PM, Hengqi Chen wrote:
On 2021/7/26 11:32 AM, Yonghong Song wrote:
On 7/25/21 7:18 AM, Hengqi Chen wrote:
Kernel functions referenced by .BTF_ids may changed from global to static
and get inlined and thus disappears from BTF. This causes kernel build
the function could be renamed or removed too.
failure when resolve_btfids do id patch for symbols in .BTF_ids in vmlinux.
Update resolve_btfids to emit warning messages and patch zero id for missing
symbols instead of aborting kernel build process.
Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx>
LGTM with one minor comment below.
Acked-by: Yonghong Song <yhs@xxxxxx>
---
tools/bpf/resolve_btfids/main.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 3ad9301b0f00..3ea19e33250d 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -291,7 +291,7 @@ static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh)
sh->sh_addralign = expected;
if (gelf_update_shdr(scn, sh) == 0) {
- printf("FAILED cannot update section header: %s\n",
+ pr_err("FAILED cannot update section header: %s\n",
elf_errmsg(-1));
return -1;
}
@@ -317,6 +317,7 @@ static int elf_collect(struct object *obj)
elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL);
if (!elf) {
+ close(fd);
pr_err("FAILED cannot create ELF descriptor: %s\n",
elf_errmsg(-1));
return -1;
@@ -484,7 +485,7 @@ static int symbols_resolve(struct object *obj)
err = libbpf_get_error(btf);
if (err) {
pr_err("FAILED: load BTF from %s: %s\n",
- obj->path, strerror(-err));
+ obj->btf ?: obj->path, strerror(-err));
Why you change "obj->path" to "obj->btf ?: obj->path"?
Note that obj->path cannot be NULL.
The diff didn't see the whole picture. Let me quote it here:
```
btf = btf__parse(obj->btf ?: obj->path, NULL);
err = libbpf_get_error(btf);
if (err) {
pr_err("FAILED: load BTF from %s: %s\n",
obj->path, strerror(-err));
return -1;
}
```
Because btf__parse parses either obj->btf or obj->path,
I think the error message should reveal this.
Okay, I see, obj->btf may not be NULL due to
OPT_STRING(0, "btf", &obj.btf, "BTF data",
"BTF data"),
How about
obj->btf ? "input BTF data" : obj->path
The error message like
FAILED: load BTF from : <error msg>
does not sound good.
Sorry, I am confused.
If obj->btf is set, say, vmlinux.btf, the message should look like:
FAILED: load BTF from vmlinux.btf: <error msg>
Otherwise, it should look like:
FAILED: load BTF from vmlinux: <error msg>
Am I missing something ?
Ah, you are right. Your patch looks good. I didn't pay attention
and thought
OPT_STRING(0, "btf", &obj.btf, "BTF data","BTF data")
is a string input for *btf data*, but actually it is actually
/sys/kernel/btf/vmlinux.
return -1;
}
[...]
