[PATCH v3 bpf-next] bpf: add a verbose message if map limit is reached

From: Anton Protopopov <aspsk@isovalent.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Jiri Olsa <jolsa@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Stanislav Fomichev <sdf@google.com>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	bpf@vger.kernel.org
Cc: Anton Protopopov <aspsk@isovalent.com>
Subject: [PATCH v3 bpf-next] bpf: add a verbose message if map limit is reached
Date: Tue,  2 Apr 2024 07:33:47 +0000	[thread overview]
Message-ID: <20240402073347.195920-1-aspsk@isovalent.com> (raw)

When more than 64 maps are used by a program and its subprograms the
verifier returns -E2BIG. Add a verbose message which highlights the
source of the error and also print the actual limit.

v1 -> v2:
  * make the message more clear (Alexey)
v2 -> v3:
  * fixed grammar (Anton)

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: John Fastabend <john.fastabend@gmail.com>
---
 kernel/bpf/verifier.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index edb650667f44..559526191ae7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18348,6 +18348,8 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
 			}
 
 			if (env->used_map_cnt >= MAX_USED_MAPS) {
+				verbose(env, "The total number of maps per program has reached the limit of %u\n",
+					MAX_USED_MAPS);
 				fdput(f);
 				return -E2BIG;
 			}
-- 
2.34.1

