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From:   Jiri Olsa <jolsa@kernel.org>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>
Cc:     netdev@vger.kernel.org, bpf@vger.kernel.org,
        lkml <linux-kernel@vger.kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCHv3 bpf-next 02/13] kallsyms: Skip the name search for empty string
Date:   Wed, 16 Mar 2022 13:24:08 +0100
Message-Id: <20220316122419.933957-3-jolsa@kernel.org>
In-Reply-To: <20220316122419.933957-1-jolsa@kernel.org>
References: <20220316122419.933957-1-jolsa@kernel.org>
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When kallsyms_lookup_name is called with empty string,
it will do futile search for it through all the symbols.

Skipping the search for empty string.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 kernel/kallsyms.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 951c93216fc4..79f2eb617a62 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -212,6 +212,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	unsigned long i;
 	unsigned int off;
 
+	/* Skip the search for empty string. */
+	if (!*name)
+		return 0;
+
 	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
 		off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf));
 
-- 
2.35.1