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Message-Id: <20211225083242.38498-2-wangqiang.wq.frank@bytedance.com>
Date: Sat, 25 Dec 2021 16:32:42 +0800
From: Qiang Wang <wangqiang.wq.frank@...edance.com>
To: ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
kafai@...com, songliubraving@...com, yhs@...com,
john.fastabend@...il.com, kpsingh@...nel.org
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org,
linux-kernel@...r.kernel.org, zhouchengming@...edance.com,
songmuchun@...edance.com, duanxiongchun@...edance.com,
shekairui@...edance.com
Subject: [PATCH 2/2] libbpf: Support repeated legacy kprobes on same function
If repeated legacy kprobes on same function in one process,
libbpf will register using the same probe name and got -EBUSY
error. So append index to the probe name format to fix this
problem.
Co-developed-by: Chengming Zhou <zhouchengming@...edance.com>
Signed-off-by: Qiang Wang <wangqiang.wq.frank@...edance.com>
Signed-off-by: Chengming Zhou <zhouchengming@...edance.com>
---
tools/lib/bpf/libbpf.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b7d6c951fa09..0c41a45ffd54 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9634,7 +9634,9 @@ static int append_to_file(const char *file, const char *fmt, ...)
static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
const char *kfunc_name, size_t offset)
{
- snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), kfunc_name, offset);
+ static int index = 0;
+ snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset
+ __sync_fetch_and_add(&index, 1));
}
static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
--
2.20.1
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