[PATCH bpf-next v3 0/2] allow kfuncs in tracepoint and perf event

[PATCH bpf-next v3 0/2] allow kfuncs in tracepoint and perf event

[JP Kobryn]

It is possible to call a cpumask kfunc within a raw tp_btf program but not
possible within tracepoint or perf event programs. Currently, the verifier
receives -EACCESS from fetch_kfunc_meta() as a result of not finding any
kfunc hook associated with these program types.

This patch series associates tracepoint and perf event program types with
the tracing hook and includes test coverage.

Pre-submission CI run: https://github.com/kernel-patches/bpf/pull/7674

v3:
	- map tracepoint and perf event progs to tracing kfunc hook
	- expand existing verifier tests for kfuncs
	- remove explicit registrations from v2
	- no longer including kprobes
v2:
	- create new kfunc hooks for tracepoint and perf event
	- map tracepoint, and perf event prog types to kfunc hooks
	- register cpumask kfuncs with prog types in focus
	- expand existing verifier tests for cpumask kfuncs
v1:
	- map tracepoint type progs to tracing kfunc hook
	- new selftests for calling cpumask kfuncs in tracepoint prog
---
JP Kobryn (2):
  bpf: allow kfuncs within tracepoint and perf event programs
  bpf/selftests: coverage for new program types using cpumask kfuncs

 kernel/bpf/btf.c                                 |  2 ++
 .../bpf/progs/verifier_kfunc_prog_types.c        | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

-- 
2.46.0

[PATCH bpf-next v3 1/2] bpf: allow kfuncs within tracepoint and perf event programs

[JP Kobryn]

Associate tracepoint and perf event program types with the kfunc tracing
hook. This allows calling kfuncs within these types of programs.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
---
 kernel/bpf/btf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 520f49f422fe..7d25ecd195ba 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -8304,6 +8304,8 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
 	case BPF_PROG_TYPE_STRUCT_OPS:
 		return BTF_KFUNC_HOOK_STRUCT_OPS;
 	case BPF_PROG_TYPE_TRACING:
+	case BPF_PROG_TYPE_TRACEPOINT:
+	case BPF_PROG_TYPE_PERF_EVENT:
 	case BPF_PROG_TYPE_LSM:
 		return BTF_KFUNC_HOOK_TRACING;
 	case BPF_PROG_TYPE_SYSCALL:
-- 
2.46.0

[PATCH bpf-next v3 2/2] bpf/selftests: coverage for tp and perf event progs using kfuncs

[JP Kobryn]

This coverage ensures that kfuncs are allowed within tracepoint and perf
event programs.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
---
 .../bpf/progs/verifier_kfunc_prog_types.c     | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_kfunc_prog_types.c b/tools/testing/selftests/bpf/progs/verifier_kfunc_prog_types.c
index cb32b0cfc84b..a509cad97e69 100644
--- a/tools/testing/selftests/bpf/progs/verifier_kfunc_prog_types.c
+++ b/tools/testing/selftests/bpf/progs/verifier_kfunc_prog_types.c
@@ -47,6 +47,22 @@ int BPF_PROG(task_kfunc_syscall)
 	return 0;
 }
 
+SEC("tracepoint")
+__success
+int BPF_PROG(task_kfunc_tracepoint)
+{
+	task_kfunc_load_test();
+	return 0;
+}
+
+SEC("perf_event")
+__success
+int BPF_PROG(task_kfunc_perf_event)
+{
+	task_kfunc_load_test();
+	return 0;
+}
+
 /*****************
  * cgroup kfuncs *
  *****************/
@@ -85,6 +101,22 @@ int BPF_PROG(cgrp_kfunc_syscall)
 	return 0;
 }
 
+SEC("tracepoint")
+__success
+int BPF_PROG(cgrp_kfunc_tracepoint)
+{
+	cgrp_kfunc_load_test();
+	return 0;
+}
+
+SEC("perf_event")
+__success
+int BPF_PROG(cgrp_kfunc_perf_event)
+{
+	cgrp_kfunc_load_test();
+	return 0;
+}
+
 /******************
  * cpumask kfuncs *
  ******************/
@@ -120,3 +152,19 @@ int BPF_PROG(cpumask_kfunc_syscall)
 	cpumask_kfunc_load_test();
 	return 0;
 }
+
+SEC("tracepoint")
+__success
+int BPF_PROG(cpumask_kfunc_tracepoint)
+{
+	cpumask_kfunc_load_test();
+	return 0;
+}
+
+SEC("perf_event")
+__success
+int BPF_PROG(cpumask_kfunc_perf_event)
+{
+	cpumask_kfunc_load_test();
+	return 0;
+}
-- 
2.46.0

Re: [PATCH bpf-next v3 0/2] allow kfuncs in tracepoint and perf event

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Thu,  5 Sep 2024 15:38:10 -0700 you wrote:
> It is possible to call a cpumask kfunc within a raw tp_btf program but not
> possible within tracepoint or perf event programs. Currently, the verifier
> receives -EACCESS from fetch_kfunc_meta() as a result of not finding any
> kfunc hook associated with these program types.
> 
> This patch series associates tracepoint and perf event program types with
> the tracing hook and includes test coverage.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v3,1/2] bpf: allow kfuncs within tracepoint and perf event programs
    https://git.kernel.org/bpf/bpf-next/c/bc638d8cb5be
  - [bpf-next,v3,2/2] bpf/selftests: coverage for tp and perf event progs using kfuncs
    https://git.kernel.org/bpf/bpf-next/c/1b3bc648f506

You are awesome, thank you!
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