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. Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Leon Hwang <[email protected]> --- 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 e07af35ed040..8c2c1d1b9094 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -474,18 +474,11 @@ 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); @@ -1226,6 +1219,7 @@ 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; @@ -1583,7 +1577,6 @@ 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
