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Subject[PATCH] libbpf: Remove kprobe_event on failed kprobe_open_legacy
Date
In a scenario where livepatch and aggrprobe coexist, the creating
kprobe_event using tracefs API will succeed, a trace event (e.g.
/debugfs/tracing/events/kprobe/XX) will exist, but perf_event_open()
will return an error.

Signed-off-by: Chuang W <nashuiliang@gmail.com>
Signed-off-by: Jingren Zhou <zhoujingren@didiglobal.com>
---
tools/lib/bpf/libbpf.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 0781fae58a06..d0a36350e22a 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -10809,10 +10809,11 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
}
type = determine_kprobe_perf_type_legacy(probe_name, retprobe);
if (type < 0) {
+ err = type;
pr_warn("failed to determine legacy kprobe event id for '%s+0x%zx': %s\n",
kfunc_name, offset,
- libbpf_strerror_r(type, errmsg, sizeof(errmsg)));
- return type;
+ libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
+ goto clear_kprobe_event;
}
attr.size = sizeof(attr);
attr.config = type;
@@ -10826,9 +10827,14 @@ static int perf_event_kprobe_open_legacy(const char *probe_name, bool retprobe,
err = -errno;
pr_warn("legacy kprobe perf_event_open() failed: %s\n",
libbpf_strerror_r(err, errmsg, sizeof(errmsg)));
- return err;
+ goto clear_kprobe_event;
}
return pfd;
+
+clear_kprobe_event:
+ /* Clear the newly added kprobe_event */
+ remove_kprobe_event_legacy(probe_name, retprobe);
+ return err;
}

struct bpf_link *
--
2.34.1
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