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From:   menglong8.dong@gmail.com
To:     andrii@kernel.org
Cc:     ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev,
        song@kernel.org, yhs@fb.com, john.fastabend@gmail.com,
        kpsingh@kernel.org, sdf@google.com, haoluo@google.com,
        jolsa@kernel.org, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, Menglong Dong <imagedong@tencent.com>
Subject: [PATCH] libbpf: replace '.' with '_' in legacy kprobe event name
Date:   Fri, 13 Jan 2023 17:34:27 +0800
Message-Id: <20230113093427.1666466-1-imagedong@tencent.com>
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From: Menglong Dong <imagedong@tencent.com>

'.' is not allowed in the event name of kprobe. Therefore, we will get a
EINVAL if the kernel function name has a '.' in legacy kprobe attach
case, such as 'icmp_reply.constprop.0'.

In order to adapt this case, we need to replace the '.' with other char
in gen_kprobe_legacy_event_name(). And I use '_' for this propose.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 tools/lib/bpf/libbpf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index fdfb1ca34ced..5d6f6675c2f2 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9994,9 +9994,16 @@ static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
 					 const char *kfunc_name, size_t offset)
 {
 	static int index = 0;
+	int i = 0;
 
 	snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset,
 		 __sync_fetch_and_add(&index, 1));
+
+	while (buf[i] != '\0') {
+		if (buf[i] == '.')
+			buf[i] = '_';
+		i++;
+	}
 }
 
 static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
-- 
2.39.0