From e18e2e70dbd1ee3099049557060067b6ec703efa Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 6 May 2024 17:13:30 -0700 Subject: libbpf: handle yet another corner case of nulling out struct_ops program There is yet another corner case where user can set STRUCT_OPS program reference in STRUCT_OPS map to NULL, but libbpf will fail to disable autoload for such BPF program. This time it's the case of "new" kernel which has type information about callback field, but user explicitly nulled-out program reference from user-space after opening BPF object. Fix, hopefully, the last remaining unhandled case. Fixes: 0737df6de946 ("libbpf: better fix for handling nulled-out struct_ops program") Fixes: f973fccd43d3 ("libbpf: handle nulled-out program in struct_ops correctly") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20240507001335.1445325-3-andrii@kernel.org Signed-off-by: Martin KaFai Lau --- tools/lib/bpf/libbpf.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 7d77a1b158ce..04de4fb81785 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1193,11 +1193,19 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map) } if (btf_is_ptr(mtype)) { - /* Update the value from the shadow type */ prog = *(void **)mdata; + /* just like for !kern_member case above, reset declaratively + * set (at compile time) program's autload to false, + * if user replaced it with another program or NULL + */ + if (st_ops->progs[i] && st_ops->progs[i] != prog) + st_ops->progs[i]->autoload = false; + + /* Update the value from the shadow type */ st_ops->progs[i] = prog; if (!prog) continue; + if (!is_valid_st_ops_program(obj, prog)) { pr_warn("struct_ops init_kern %s: member %s is not a struct_ops program\n", map->name, mname); -- cgit v1.2.3-70-g09d2