[PATCH bpf-next v2 01/21] bpf: Initialize ftrace_managed in bpf_trampoline_get()
flat view
COOLING4d
From: Leon Hwang <hidden>
Date: 2026-10-12 15:41:24
Also in:
bpf, linux-kselftest, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Revision v2 of 2 in this series.
Revisions (2)
- v1 [diff vs current]
- v2 current
A trampoline managed by ftrace is determined by its target, that said ftrace_managed is already known when the trampoline is initialized. so, set 'ftrace_managed = tr->ip != 0' in bpf_trampoline_get() instead of relying on the first regular or tracing_multi attachment to set it. This makes the backend selection independent of attachment order and keeps the registration callbacks focused on installing the trampoline. No functional change intended. Signed-off-by: Leon Hwang <redacted> --- kernel/bpf/trampoline.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 24edb59238f3..17f2a8133f61 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c@@ -475,18 +475,11 @@ static int register_fentry(struct bpf_trampoline *tr, struct bpf_tramp_image *im void *data __maybe_unused) { void *new_addr = im->image; - void *ip = tr->func.addr; - unsigned long faddr; int ret; - faddr = ftrace_location((unsigned long)ip); - if (faddr) { + if (tr->func.ftrace_managed) { if (!tr->fops) return -ENOTSUPP; - tr->func.ftrace_managed = true; - } - - if (tr->func.ftrace_managed) { ret = direct_ops_add(tr, new_addr); } else { ret = bpf_trampoline_update_fentry(tr, 0, NULL, new_addr);
@@ -1286,6 +1279,7 @@ struct bpf_trampoline *bpf_trampoline_get(u64 key, memcpy(&tr->func.model, &tgt_info->fmodel, sizeof(tgt_info->fmodel)); tr->func.addr = (void *)tgt_info->tgt_addr; + tr->func.ftrace_managed = tr->ip != 0; out: trampoline_unlock(tr); return tr;
@@ -1649,7 +1643,6 @@ static int register_fentry_multi(struct bpf_trampoline *tr, struct bpf_tramp_ima if (bpf_trampoline_use_jmp(tr->flags)) addr = ftrace_jmp_set(addr); - tr->func.ftrace_managed = true; ftrace_hash_add(data->reg, data->entry, ip, addr); tr->cur_image = im; return 0;
--
2.55.0