* [PATCH bpf-next] libbpf: Fix expected_attach_type set when kernel not support
@ 2024-09-13 12:16 Tao Chen
2024-09-13 13:48 ` Jiri Olsa
0 siblings, 1 reply; 3+ messages in thread
From: Tao Chen @ 2024-09-13 12:16 UTC (permalink / raw)
To: Andrii Nakryiko, Eduard Zingerman, Daniel Borkmann,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa
Cc: bpf, linux-kernel, Tao Chen
The commit "5902da6d8a52" set expected_attach_type again with
filed of bpf_program after libpf_prepare_prog_load, which makes
expected_attach_type = 0 no sense when kenrel not support the
attach_type feature, so fix it.
Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt")
Signed-off-by: Tao Chen <chen.dylane@gmail.com>
---
tools/lib/bpf/libbpf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 219facd0e66e..9035edf763a3 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7343,7 +7343,7 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog,
/* old kernels might not support specifying expected_attach_type */
if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE))
- opts->expected_attach_type = 0;
+ prog->expected_attach_type = 0;
if (def & SEC_SLEEPABLE)
opts->prog_flags |= BPF_F_SLEEPABLE;
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH bpf-next] libbpf: Fix expected_attach_type set when kernel not support 2024-09-13 12:16 [PATCH bpf-next] libbpf: Fix expected_attach_type set when kernel not support Tao Chen @ 2024-09-13 13:48 ` Jiri Olsa 2024-09-13 15:14 ` Tao Chen 0 siblings, 1 reply; 3+ messages in thread From: Jiri Olsa @ 2024-09-13 13:48 UTC (permalink / raw) To: Tao Chen Cc: Andrii Nakryiko, Eduard Zingerman, Daniel Borkmann, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, bpf, linux-kernel On Fri, Sep 13, 2024 at 08:16:27PM +0800, Tao Chen wrote: > The commit "5902da6d8a52" set expected_attach_type again with > filed of bpf_program after libpf_prepare_prog_load, which makes > expected_attach_type = 0 no sense when kenrel not support the > attach_type feature, so fix it. > > Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt") > Signed-off-by: Tao Chen <chen.dylane@gmail.com> > --- > tools/lib/bpf/libbpf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 219facd0e66e..9035edf763a3 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -7343,7 +7343,7 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, > > /* old kernels might not support specifying expected_attach_type */ > if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE)) > - opts->expected_attach_type = 0; > + prog->expected_attach_type = 0; > > if (def & SEC_SLEEPABLE) > opts->prog_flags |= BPF_F_SLEEPABLE; > -- > 2.25.1 > good catch! thanks I can't remember why it was needed, perhaps we should go back to where it was before? I'm guessing prog->expected_attach_type might not get updated properly and that might cause issues, not sure thanks, jirka --- diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 219facd0e66e..df2244397ba1 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7353,7 +7353,7 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, /* special check for usdt to use uprobe_multi link */ if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) - prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; + opts->expected_attach_type = BPF_TRACE_UPROBE_MULTI; if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { int btf_obj_fd = 0, btf_type_id = 0, err; @@ -7443,6 +7443,7 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog load_attr.attach_btf_id = prog->attach_btf_id; load_attr.kern_version = kern_version; load_attr.prog_ifindex = prog->prog_ifindex; + load_attr.expected_attach_type = prog->expected_attach_type; /* specify func_info/line_info only if kernel supports them */ if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { @@ -7474,9 +7475,6 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog insns_cnt = prog->insns_cnt; } - /* allow prog_prepare_load_fn to change expected_attach_type */ - load_attr.expected_attach_type = prog->expected_attach_type; - if (obj->gen_loader) { bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, license, insns, insns_cnt, &load_attr, ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] libbpf: Fix expected_attach_type set when kernel not support 2024-09-13 13:48 ` Jiri Olsa @ 2024-09-13 15:14 ` Tao Chen 0 siblings, 0 replies; 3+ messages in thread From: Tao Chen @ 2024-09-13 15:14 UTC (permalink / raw) To: Jiri Olsa Cc: Andrii Nakryiko, Eduard Zingerman, Daniel Borkmann, Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, bpf, linux-kernel 在 2024/9/13 21:48, Jiri Olsa 写道: > On Fri, Sep 13, 2024 at 08:16:27PM +0800, Tao Chen wrote: >> The commit "5902da6d8a52" set expected_attach_type again with >> filed of bpf_program after libpf_prepare_prog_load, which makes >> expected_attach_type = 0 no sense when kenrel not support the >> attach_type feature, so fix it. >> >> Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt") >> Signed-off-by: Tao Chen <chen.dylane@gmail.com> >> --- >> tools/lib/bpf/libbpf.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c >> index 219facd0e66e..9035edf763a3 100644 >> --- a/tools/lib/bpf/libbpf.c >> +++ b/tools/lib/bpf/libbpf.c >> @@ -7343,7 +7343,7 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, >> >> /* old kernels might not support specifying expected_attach_type */ >> if ((def & SEC_EXP_ATTACH_OPT) && !kernel_supports(prog->obj, FEAT_EXP_ATTACH_TYPE)) >> - opts->expected_attach_type = 0; >> + prog->expected_attach_type = 0; >> >> if (def & SEC_SLEEPABLE) >> opts->prog_flags |= BPF_F_SLEEPABLE; >> -- >> 2.25.1 >> > > good catch! thanks > > I can't remember why it was needed, perhaps we should go back to where it > was before? > > I'm guessing prog->expected_attach_type might not get updated properly and > that might cause issues, not sure > > thanks, > jirka > > > --- > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 219facd0e66e..df2244397ba1 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -7353,7 +7353,7 @@ static int libbpf_prepare_prog_load(struct bpf_program *prog, > > /* special check for usdt to use uprobe_multi link */ > if ((def & SEC_USDT) && kernel_supports(prog->obj, FEAT_UPROBE_MULTI_LINK)) > - prog->expected_attach_type = BPF_TRACE_UPROBE_MULTI; > + opts->expected_attach_type = BPF_TRACE_UPROBE_MULTI; > > if ((def & SEC_ATTACH_BTF) && !prog->attach_btf_id) { > int btf_obj_fd = 0, btf_type_id = 0, err; > @@ -7443,6 +7443,7 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog > load_attr.attach_btf_id = prog->attach_btf_id; > load_attr.kern_version = kern_version; > load_attr.prog_ifindex = prog->prog_ifindex; > + load_attr.expected_attach_type = prog->expected_attach_type; > > /* specify func_info/line_info only if kernel supports them */ > if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { > @@ -7474,9 +7475,6 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog > insns_cnt = prog->insns_cnt; > } > > - /* allow prog_prepare_load_fn to change expected_attach_type */ > - load_attr.expected_attach_type = prog->expected_attach_type; > - > if (obj->gen_loader) { > bpf_gen__prog_load(obj->gen_loader, prog->type, prog->name, > license, insns, insns_cnt, &load_attr, Hi, Jiri, thank you for your reply. It looks better your way, i will send it in v2. -- Best Regards Dylane Chen ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-09-13 15:14 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2024-09-13 12:16 [PATCH bpf-next] libbpf: Fix expected_attach_type set when kernel not support Tao Chen 2024-09-13 13:48 ` Jiri Olsa 2024-09-13 15:14 ` Tao Chen
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