No logic changed, just add specific btf name when core info
print, maybe it seems more understandable.
Signed-off-by: Tao Chen <[email protected]>
---
tools/lib/bpf/libbpf.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index afd09571c482..b32154288b4a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -5653,7 +5653,8 @@ static int load_module_btfs(struct bpf_object *obj)
}
static struct bpf_core_cand_list *
-bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
+bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id,
+ const char *targ_btf_path)
{
struct bpf_core_cand local_cand = {};
struct bpf_core_cand_list *cands;
@@ -5680,7 +5681,8 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
/* Attempt to find target candidates in vmlinux BTF first */
main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
- err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
+ err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf,
+ targ_btf_path ?: "vmlinux", 1, cands);
if (err)
goto err_out;
@@ -5793,7 +5795,8 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
int relo_idx,
const struct btf *local_btf,
struct hashmap *cand_cache,
- struct bpf_core_relo_res *targ_res)
+ struct bpf_core_relo_res *targ_res,
+ const char *targ_btf_path)
{
struct bpf_core_spec specs_scratch[3] = {};
struct bpf_core_cand_list *cands = NULL;
@@ -5813,7 +5816,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
!hashmap__find(cand_cache, local_id, &cands)) {
- cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
+ cands = bpf_core_find_cands(prog->obj, local_btf, local_id, targ_btf_path);
if (IS_ERR(cands)) {
pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
prog_name, relo_idx, local_id, btf_kind_str(local_type),
@@ -5920,7 +5923,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
if (prog->obj->gen_loader)
continue;
- err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
+ err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res,
+ targ_btf_path);
if (err) {
pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
prog->name, i, err);
--
2.34.1
On Thu, Mar 21, 2024 at 10:04 AM Tao Chen <[email protected]> wrote:
>
> No logic changed, just add specific btf name when core info
> print, maybe it seems more understandable.
>
> Signed-off-by: Tao Chen <[email protected]>
> ---
> tools/lib/bpf/libbpf.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
Can you elaborate on what problem you are trying to solve?
Conceptually libbpf does look for types in vmlinux (meaning main
kernel BTF), even if user overrides BTF location (presumably because
of old kernel). So even when we emit "vmlinux" in logs, it seems
correct.
pw-bot: cr
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index afd09571c482..b32154288b4a 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -5653,7 +5653,8 @@ static int load_module_btfs(struct bpf_object *obj)
> }
>
> static struct bpf_core_cand_list *
> -bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
> +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id,
> + const char *targ_btf_path)
> {
> struct bpf_core_cand local_cand = {};
> struct bpf_core_cand_list *cands;
> @@ -5680,7 +5681,8 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
>
> /* Attempt to find target candidates in vmlinux BTF first */
> main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
> - err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
> + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf,
> + targ_btf_path ?: "vmlinux", 1, cands);
> if (err)
> goto err_out;
>
> @@ -5793,7 +5795,8 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
> int relo_idx,
> const struct btf *local_btf,
> struct hashmap *cand_cache,
> - struct bpf_core_relo_res *targ_res)
> + struct bpf_core_relo_res *targ_res,
> + const char *targ_btf_path)
> {
> struct bpf_core_spec specs_scratch[3] = {};
> struct bpf_core_cand_list *cands = NULL;
> @@ -5813,7 +5816,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
>
> if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
> !hashmap__find(cand_cache, local_id, &cands)) {
> - cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
> + cands = bpf_core_find_cands(prog->obj, local_btf, local_id, targ_btf_path);
> if (IS_ERR(cands)) {
> pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
> prog_name, relo_idx, local_id, btf_kind_str(local_type),
> @@ -5920,7 +5923,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
> if (prog->obj->gen_loader)
> continue;
>
> - err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
> + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res,
> + targ_btf_path);
> if (err) {
> pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
> prog->name, i, err);
> --
> 2.34.1
>
Hi, Nakryiko, thank you for your reply. I try to familiarize with core
in libbpf， the debug info is really helpful for me. But i use the old
kernel btf, so origion debuginfo like:
struct task_struct___x: found target candidate [130] struct
task_struct in [vmlinux]
I think it may be more clear, if we print btf name when we use old
kernel btf like:
struct task_struct___x: found target candidate [130] struct
task_struct in [/boot/***.btf]
The patch just solve debug info show for newbies above.
在 2024/3/22 上午2:52, Andrii Nakryiko 写道:
> On Thu, Mar 21, 2024 at 10:04 AM Tao Chen <[email protected]> wrote:
>>
>> No logic changed, just add specific btf name when core info
>> print, maybe it seems more understandable.
>>
>> Signed-off-by: Tao Chen <[email protected]>
>> ---
>> tools/lib/bpf/libbpf.c | 14 +++++++++-----
>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>
>
> Can you elaborate on what problem you are trying to solve?
> Conceptually libbpf does look for types in vmlinux (meaning main
> kernel BTF), even if user overrides BTF location (presumably because
> of old kernel). So even when we emit "vmlinux" in logs, it seems
> correct.
>
> pw-bot: cr
>
>
>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>> index afd09571c482..b32154288b4a 100644
>> --- a/tools/lib/bpf/libbpf.c
>> +++ b/tools/lib/bpf/libbpf.c
>> @@ -5653,7 +5653,8 @@ static int load_module_btfs(struct bpf_object *obj)
>> }
>>
>> static struct bpf_core_cand_list *
>> -bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
>> +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id,
>> + const char *targ_btf_path)
>> {
>> struct bpf_core_cand local_cand = {};
>> struct bpf_core_cand_list *cands;
>> @@ -5680,7 +5681,8 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
>>
>> /* Attempt to find target candidates in vmlinux BTF first */
>> main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
>> - err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
>> + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf,
>> + targ_btf_path ?: "vmlinux", 1, cands);
>> if (err)
>> goto err_out;
>>
>> @@ -5793,7 +5795,8 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
>> int relo_idx,
>> const struct btf *local_btf,
>> struct hashmap *cand_cache,
>> - struct bpf_core_relo_res *targ_res)
>> + struct bpf_core_relo_res *targ_res,
>> + const char *targ_btf_path)
>> {
>> struct bpf_core_spec specs_scratch[3] = {};
>> struct bpf_core_cand_list *cands = NULL;
>> @@ -5813,7 +5816,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
>>
>> if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
>> !hashmap__find(cand_cache, local_id, &cands)) {
>> - cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
>> + cands = bpf_core_find_cands(prog->obj, local_btf, local_id, targ_btf_path);
>> if (IS_ERR(cands)) {
>> pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
>> prog_name, relo_idx, local_id, btf_kind_str(local_type),
>> @@ -5920,7 +5923,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
>> if (prog->obj->gen_loader)
>> continue;
>>
>> - err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
>> + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res,
>> + targ_btf_path);
>> if (err) {
>> pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
>> prog->name, i, err);
>> --
>> 2.34.1
>>
On Fri, Mar 22, 2024 at 6:37 AM Tao Chen <[email protected]> wrote:
>
> Hi, Nakryiko, thank you for your reply. I try to familiarize with core
> in libbpf， the debug info is really helpful for me. But i use the old
> kernel btf, so origion debuginfo like:
> struct task_struct___x: found target candidate [130] struct
> task_struct in [vmlinux]
the idea here is to not emit path to BTF (otherwise we normally should
emit [/sys/kernel/btf/vmlinux], but rather distinguish whether it's a
kernel BTF ([vmlinux]) or some kernel module BTF ([<module-name>]).
In your case you are overriding vmlinux BTF by using btf_custom_path
option (so you should know where to find it, if you need to debug
something). It's still, conceptually, a [vmlinux], and I'd like to
keep it this way.
> I think it may be more clear, if we print btf name when we use old
> kernel btf like:
> struct task_struct___x: found target candidate [130] struct
> task_struct in [/boot/***.btf]
> The patch just solve debug info show for newbies above.
>
> 在 2024/3/22 上午2:52, Andrii Nakryiko 写道:
> > On Thu, Mar 21, 2024 at 10:04 AM Tao Chen <[email protected]> wrote:
> >>
> >> No logic changed, just add specific btf name when core info
> >> print, maybe it seems more understandable.
> >>
> >> Signed-off-by: Tao Chen <[email protected]>
> >> ---
> >> tools/lib/bpf/libbpf.c | 14 +++++++++-----
> >> 1 file changed, 9 insertions(+), 5 deletions(-)
> >>
> >
> > Can you elaborate on what problem you are trying to solve?
> > Conceptually libbpf does look for types in vmlinux (meaning main
> > kernel BTF), even if user overrides BTF location (presumably because
> > of old kernel). So even when we emit "vmlinux" in logs, it seems
> > correct.
> >
> > pw-bot: cr
> >
> >
> >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> >> index afd09571c482..b32154288b4a 100644
> >> --- a/tools/lib/bpf/libbpf.c
> >> +++ b/tools/lib/bpf/libbpf.c
> >> @@ -5653,7 +5653,8 @@ static int load_module_btfs(struct bpf_object *obj)
> >> }
> >>
> >> static struct bpf_core_cand_list *
> >> -bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
> >> +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id,
> >> + const char *targ_btf_path)
> >> {
> >> struct bpf_core_cand local_cand = {};
> >> struct bpf_core_cand_list *cands;
> >> @@ -5680,7 +5681,8 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
> >>
> >> /* Attempt to find target candidates in vmlinux BTF first */
> >> main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
> >> - err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
> >> + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf,
> >> + targ_btf_path ?: "vmlinux", 1, cands);
> >> if (err)
> >> goto err_out;
> >>
> >> @@ -5793,7 +5795,8 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
> >> int relo_idx,
> >> const struct btf *local_btf,
> >> struct hashmap *cand_cache,
> >> - struct bpf_core_relo_res *targ_res)
> >> + struct bpf_core_relo_res *targ_res,
> >> + const char *targ_btf_path)
> >> {
> >> struct bpf_core_spec specs_scratch[3] = {};
> >> struct bpf_core_cand_list *cands = NULL;
> >> @@ -5813,7 +5816,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
> >>
> >> if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
> >> !hashmap__find(cand_cache, local_id, &cands)) {
> >> - cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
> >> + cands = bpf_core_find_cands(prog->obj, local_btf, local_id, targ_btf_path);
> >> if (IS_ERR(cands)) {
> >> pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
> >> prog_name, relo_idx, local_id, btf_kind_str(local_type),
> >> @@ -5920,7 +5923,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
> >> if (prog->obj->gen_loader)
> >> continue;
> >>
> >> - err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
> >> + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res,
> >> + targ_btf_path);
> >> if (err) {
> >> pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
> >> prog->name, i, err);
> >> --
> >> 2.34.1
> >>
Got it, thanks for your detailed reply.
在 2024/3/23 上午1:57, Andrii Nakryiko 写道:
> On Fri, Mar 22, 2024 at 6:37 AM Tao Chen <[email protected]> wrote:
>>
>> Hi, Nakryiko, thank you for your reply. I try to familiarize with core
>> in libbpf， the debug info is really helpful for me. But i use the old
>> kernel btf, so origion debuginfo like:
>> struct task_struct___x: found target candidate [130] struct
>> task_struct in [vmlinux]
>
> the idea here is to not emit path to BTF (otherwise we normally should
> emit [/sys/kernel/btf/vmlinux], but rather distinguish whether it's a
> kernel BTF ([vmlinux]) or some kernel module BTF ([<module-name>]).
>
> In your case you are overriding vmlinux BTF by using btf_custom_path
> option (so you should know where to find it, if you need to debug
> something). It's still, conceptually, a [vmlinux], and I'd like to
> keep it this way.
>
>> I think it may be more clear, if we print btf name when we use old
>> kernel btf like:
>> struct task_struct___x: found target candidate [130] struct
>> task_struct in [/boot/***.btf]
>> The patch just solve debug info show for newbies above.
>>
>> 在 2024/3/22 上午2:52, Andrii Nakryiko 写道:
>>> On Thu, Mar 21, 2024 at 10:04 AM Tao Chen <[email protected]> wrote:
>>>>
>>>> No logic changed, just add specific btf name when core info
>>>> print, maybe it seems more understandable.
>>>>
>>>> Signed-off-by: Tao Chen <[email protected]>
>>>> ---
>>>> tools/lib/bpf/libbpf.c | 14 +++++++++-----
>>>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>>>
>>>
>>> Can you elaborate on what problem you are trying to solve?
>>> Conceptually libbpf does look for types in vmlinux (meaning main
>>> kernel BTF), even if user overrides BTF location (presumably because
>>> of old kernel). So even when we emit "vmlinux" in logs, it seems
>>> correct.
>>>
>>> pw-bot: cr
>>>
>>>
>>>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>>>> index afd09571c482..b32154288b4a 100644
>>>> --- a/tools/lib/bpf/libbpf.c
>>>> +++ b/tools/lib/bpf/libbpf.c
>>>> @@ -5653,7 +5653,8 @@ static int load_module_btfs(struct bpf_object *obj)
>>>> }
>>>>
>>>> static struct bpf_core_cand_list *
>>>> -bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id)
>>>> +bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 local_type_id,
>>>> + const char *targ_btf_path)
>>>> {
>>>> struct bpf_core_cand local_cand = {};
>>>> struct bpf_core_cand_list *cands;
>>>> @@ -5680,7 +5681,8 @@ bpf_core_find_cands(struct bpf_object *obj, const struct btf *local_btf, __u32 l
>>>>
>>>> /* Attempt to find target candidates in vmlinux BTF first */
>>>> main_btf = obj->btf_vmlinux_override ?: obj->btf_vmlinux;
>>>> - err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf, "vmlinux", 1, cands);
>>>> + err = bpf_core_add_cands(&local_cand, local_essent_len, main_btf,
>>>> + targ_btf_path ?: "vmlinux", 1, cands);
>>>> if (err)
>>>> goto err_out;
>>>>
>>>> @@ -5793,7 +5795,8 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
>>>> int relo_idx,
>>>> const struct btf *local_btf,
>>>> struct hashmap *cand_cache,
>>>> - struct bpf_core_relo_res *targ_res)
>>>> + struct bpf_core_relo_res *targ_res,
>>>> + const char *targ_btf_path)
>>>> {
>>>> struct bpf_core_spec specs_scratch[3] = {};
>>>> struct bpf_core_cand_list *cands = NULL;
>>>> @@ -5813,7 +5816,7 @@ static int bpf_core_resolve_relo(struct bpf_program *prog,
>>>>
>>>> if (relo->kind != BPF_CORE_TYPE_ID_LOCAL &&
>>>> !hashmap__find(cand_cache, local_id, &cands)) {
>>>> - cands = bpf_core_find_cands(prog->obj, local_btf, local_id);
>>>> + cands = bpf_core_find_cands(prog->obj, local_btf, local_id, targ_btf_path);
>>>> if (IS_ERR(cands)) {
>>>> pr_warn("prog '%s': relo #%d: target candidate search failed for [%d] %s %s: %ld\n",
>>>> prog_name, relo_idx, local_id, btf_kind_str(local_type),
>>>> @@ -5920,7 +5923,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
>>>> if (prog->obj->gen_loader)
>>>> continue;
>>>>
>>>> - err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res);
>>>> + err = bpf_core_resolve_relo(prog, rec, i, obj->btf, cand_cache, &targ_res,
>>>> + targ_btf_path);
>>>> if (err) {
>>>> pr_warn("prog '%s': relo #%d: failed to relocate: %d\n",
>>>> prog->name, i, err);
>>>> --
>>>> 2.34.1
>>>>