From 2655144fb49bae26eae038c6d056f824a7db2726 Mon Sep 17 00:00:00 2001 From: Chuang Wang Date: Wed, 29 Jun 2022 23:18:47 +0800 Subject: [PATCH] libbpf: Cleanup the legacy uprobe_event on failed add/attach_event() A potential scenario, when an error is returned after add_uprobe_event_legacy() in perf_event_uprobe_open_legacy(), or bpf_program__attach_perf_event_opts() in bpf_program__attach_uprobe_opts() returns an error, the uprobe_event that was previously created is not cleaned. So, with this patch, when an error is returned, fix this by adding remove_uprobe_event_legacy() Signed-off-by: Chuang Wang Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220629151848.65587-4-nashuiliang@gmail.com --- tools/lib/bpf/libbpf.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 571acd614dce8..cb49408eb298d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -10248,9 +10248,10 @@ static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe, } type = determine_uprobe_perf_type_legacy(probe_name, retprobe); if (type < 0) { + err = type; pr_warn("failed to determine legacy uprobe event id for %s:0x%zx: %d\n", - binary_path, offset, type); - return type; + binary_path, offset, err); + goto err_clean_legacy; } memset(&attr, 0, sizeof(attr)); @@ -10265,9 +10266,14 @@ static int perf_event_uprobe_open_legacy(const char *probe_name, bool retprobe, if (pfd < 0) { err = -errno; pr_warn("legacy uprobe perf_event_open() failed: %d\n", err); - return err; + goto err_clean_legacy; } return pfd; + +err_clean_legacy: + /* Clear the newly added legacy uprobe_event */ + remove_uprobe_event_legacy(probe_name, retprobe); + return err; } /* Return next ELF section of sh_type after scn, or first of that type if scn is NULL. */ @@ -10601,7 +10607,7 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, prog->name, retprobe ? "uretprobe" : "uprobe", binary_path, func_offset, libbpf_strerror_r(err, errmsg, sizeof(errmsg))); - goto err_out; + goto err_clean_legacy; } if (legacy) { struct bpf_link_perf *perf_link = container_of(link, struct bpf_link_perf, link); @@ -10611,10 +10617,13 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, perf_link->legacy_is_retprobe = retprobe; } return link; + +err_clean_legacy: + if (legacy) + remove_uprobe_event_legacy(legacy_probe, retprobe); err_out: free(legacy_probe); return libbpf_err_ptr(err); - } /* Format of u[ret]probe section definition supporting auto-attach: -- 2.30.2