netdev - [PATCH bpf-next v2 02/11] bpf: Avoid storing modifier to info->btf

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Date:   Fri, 20 Dec 2019 22:25:59 -0800
From:   Martin KaFai Lau <kafai@...com>
To:     <bpf@...r.kernel.org>
CC:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        David Miller <davem@...emloft.net>, <kernel-team@...com>,
        <netdev@...r.kernel.org>
Subject: [PATCH bpf-next v2 02/11] bpf: Avoid storing modifier to info->btf_id

info->btf_id expects the btf_id of a struct, so it should
store the final result after skipping modifiers (if any).

It also takes this chanace to add a missing newline in one of the
bpf_log() messages.

Acked-by: Yonghong Song <yhs@...com>
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
 kernel/bpf/btf.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 7d40da240891..88359a4bccb0 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3696,7 +3696,6 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 
 	/* this is a pointer to another type */
 	info->reg_type = PTR_TO_BTF_ID;
-	info->btf_id = t->type;
 
 	if (tgt_prog) {
 		ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type);
@@ -3707,10 +3706,14 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 			return false;
 		}
 	}
+
+	info->btf_id = t->type;
 	t = btf_type_by_id(btf, t->type);
 	/* skip modifiers */
-	while (btf_type_is_modifier(t))
+	while (btf_type_is_modifier(t)) {
+		info->btf_id = t->type;
 		t = btf_type_by_id(btf, t->type);
+	}
 	if (!btf_type_is_struct(t)) {
 		bpf_log(log,
 			"func '%s' arg%d type %s is not a struct\n",
@@ -3736,7 +3739,7 @@ int btf_struct_access(struct bpf_verifier_log *log,
 again:
 	tname = __btf_name_by_offset(btf_vmlinux, t->name_off);
 	if (!btf_type_is_struct(t)) {
-		bpf_log(log, "Type '%s' is not a struct", tname);
+		bpf_log(log, "Type '%s' is not a struct\n", tname);
 		return -EINVAL;
 	}
 
-- 
2.17.1