[PATCH v4 1/3] bpf: bpf_prog_array_copy() should return -ENOENT if exclude_prog not found
From: Sean Young <sean@mess.org>
Date: 2018-05-18 14:07:41
Also in:
linux-media, lkml
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
This makes is it possible for bpf prog detach to return -ENOENT. Signed-off-by: Sean Young <sean@mess.org> --- kernel/bpf/core.c | 11 +++++++++-- kernel/trace/bpf_trace.c | 2 ++ 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 2194c6a9df42..198848837783 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c@@ -1566,6 +1566,7 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, int new_prog_cnt, carry_prog_cnt = 0; struct bpf_prog **existing_prog; struct bpf_prog_array *array; + bool found_exclude = false; int new_prog_idx = 0; /* Figure out how many existing progs we need to carry over to
@@ -1574,14 +1575,20 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, if (old_array) { existing_prog = old_array->progs; for (; *existing_prog; existing_prog++) { - if (*existing_prog != exclude_prog && - *existing_prog != &dummy_bpf_prog.prog) + if (*existing_prog == exclude_prog) { + found_exclude = true; + continue; + } + if (*existing_prog != &dummy_bpf_prog.prog) carry_prog_cnt++; if (*existing_prog == include_prog) return -EEXIST; } } + if (exclude_prog && !found_exclude) + return -ENOENT; + /* How many progs (not NULL) will be in the new array? */ new_prog_cnt = carry_prog_cnt; if (include_prog)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index ce2cbbff27e4..daf36acb2a17 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -1005,6 +1005,8 @@ void perf_event_detach_bpf_prog(struct perf_event *event) old_array = event->tp_event->prog_array; ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); + if (ret == -ENOENT) + goto unlock; if (ret < 0) { bpf_prog_array_delete_safe(old_array, event->prog); } else {
--
2.17.0