uprobe and kprobe programs have the same program type, KPROBE, which is
currently not allowed to load sleepable programs.
To avoid adding a new UPROBE type, we instead allow sleepable KPROBE
programs to load and defer the is-it-actually-a-uprobe-program check
to attachment time, where we're already validating the corresponding
perf_event.
A corollary of this patch is that you can now load a sleepable kprobe
program but cannot attach it.
Signed-off-by: Delyan Kratunov <delyank@xxxxxx>
---
kernel/bpf/syscall.c | 8 ++++++++
kernel/bpf/verifier.c | 4 ++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index e9e3e49c0eb7..3ce923f489d7 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3009,6 +3009,14 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
}
event = perf_file->private_data;
+ if (prog->aux->sleepable) {
+ if (!event->tp_event || (event->tp_event->flags & TRACE_EVENT_FL_UPROBE) == 0) {
+ err = -EINVAL;
+ bpf_link_cleanup(&link_primer);
+ goto out_put_file;
+ }
+ }
+
err = perf_event_set_bpf_prog(event, prog, attr->link_create.perf_event.bpf_cookie);
if (err) {
bpf_link_cleanup(&link_primer);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 71827d14724a..c6258118dd75 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -14313,8 +14313,8 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
}
if (prog->aux->sleepable && prog->type != BPF_PROG_TYPE_TRACING &&
- prog->type != BPF_PROG_TYPE_LSM) {
- verbose(env, "Only fentry/fexit/fmod_ret and lsm programs can be sleepable\n");
+ prog->type != BPF_PROG_TYPE_LSM && prog->type != BPF_PROG_TYPE_KPROBE) {
+ verbose(env, "Only fentry/fexit/fmod_ret, lsm, and kprobe/uprobe programs can be sleepable\n");
return -EINVAL;
}
--
2.35.1
