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libbpf: Cleanup the legacy uprobe_event on failed add/attach_event()

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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 <nashuiliang@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220629151848.65587-4-nashuiliang@gmail.com
This commit is contained in:
Chuang Wang 2022-06-29 23:18:47 +08:00 committed by Andrii Nakryiko
parent 5666fc997c
commit 2655144fb4
1 changed files with 14 additions and 5 deletions
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19
tools/lib/bpf/libbpf.c
View file

@ -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: