[PATCH 14/14] bpf: Sort bpf kallsyms symbols
From: Jiri Olsa <jolsa@kernel.org>
Date: 2020-02-08 15:43:15
Also in:
bpf
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
Currently we don't sort bpf_kallsyms and display symbols in proc/kallsyms as they come in via __bpf_ksym_add. Using the latch tree to get the next bpf_ksym object and insert the new symbol ahead of it. Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- kernel/bpf/core.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 50af5dcf7ff9..c63ff34b2128 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c@@ -651,9 +651,30 @@ static struct latch_tree_root bpf_progs_tree __cacheline_aligned; static void __bpf_ksym_add(struct bpf_ksym *ksym) { + struct list_head *head = &bpf_kallsyms; + WARN_ON_ONCE(!list_empty(&ksym->lnode)); - list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); latch_tree_insert(&ksym->tnode, &bpf_kallsyms_tree, &bpf_kallsyms_tree_ops); + + /* + * Add ksym into bpf_kallsyms in ordered position, + * which is prepared for us by latch tree addition. + * + * Find out the next symbol and insert ksym right + * ahead of it. If ksym is the last one, just tail + * add to the bpf_kallsyms. + */ + if (!list_empty(&bpf_kallsyms)) { + struct rb_node *next = rb_next(&ksym->tnode.node[0]); + + if (next) { + struct bpf_ksym *ptr; + + ptr = container_of(next, struct bpf_ksym, tnode.node[0]); + head = &ptr->lnode; + } + } + list_add_tail_rcu(&ksym->lnode, head); } void bpf_ksym_add(struct bpf_ksym *ksym)
--
2.24.1