[PATCH v3 2/5] tracing: Use __free() in trace_probe for cleanup

Masami Hiramatsu (Google)
2025-01-07T11:50:30Z

From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Use __free() in trace_probe to cleanup some gotos.

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
kernel/trace/trace_probe.c | 52 +++++++++++++++-----------------------------
1 file changed, 18 insertions(+), 34 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 16a5e368e7b7..bf6a7b81ae95 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1409,7 +1409,7 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code, *tmp = NULL;
- char *type, *arg;
+ char *type, *arg __free(kfree) = NULL;
int ret, len;

len = strlen(argv);
@@ -1426,22 +1426,16 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
return -ENOMEM;

parg->comm = kstrdup(arg, GFP_KERNEL);
- if (!parg->comm) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!parg->comm)
+ return -ENOMEM;

type = parse_probe_arg_type(arg, parg, ctx);
- if (IS_ERR(type)) {
- ret = PTR_ERR(type);
- goto out;
- }
+ if (IS_ERR(type))
+ return PTR_ERR(type);

code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
- if (!code) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!code)
+ return -ENOMEM;
code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;

ctx->last_type = NULL;
@@ -1497,8 +1491,6 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
kfree(code->data);
}
kfree(tmp);
-out:
- kfree(arg);

return ret;
}
@@ -1668,7 +1660,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
{
const struct btf_param *params = NULL;
int i, j, n, used, ret, args_idx = -1;
- const char **new_argv = NULL;
+ const char **new_argv __free(kfree) = NULL;

ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
if (ret < 0)
@@ -1707,7 +1699,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
ret = sprint_nth_btf_arg(n, "", buf + used,
bufsize - used, ctx);
if (ret < 0)
- goto error;
+ return ERR_PTR(ret);

new_argv[j++] = buf + used;
used += ret + 1;
@@ -1721,25 +1713,20 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
n = simple_strtoul(argv[i] + 4, &type, 10);
if (type && !(*type == ':' || *type == '\0')) {
trace_probe_log_err(0, BAD_VAR);
- ret = -ENOENT;
- goto error;
+ return ERR_PTR(-ENOENT);
}
/* Note: $argN starts from $arg1 */
ret = sprint_nth_btf_arg(n - 1, type, buf + used,
bufsize - used, ctx);
if (ret < 0)
- goto error;
+ return ERR_PTR(ret);
new_argv[j++] = buf + used;
used += ret + 1;
} else
new_argv[j++] = argv[i];
}

- return new_argv;
-
-error:
- kfree(new_argv);
- return ERR_PTR(ret);
+ return_ptr(new_argv);
}

/* @buf: *buf must be equal to NULL. Caller must to free *buf */
@@ -1747,14 +1734,14 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
{
int i, used, ret;
const int bufsize = MAX_DENTRY_ARGS_LEN;
- char *tmpbuf = NULL;
+ char *tmpbuf __free(kfree) = NULL;

if (*buf)
return -EINVAL;

used = 0;
for (i = 0; i < argc; i++) {
- char *tmp;
+ char *tmp __free(kfree) = NULL;
char *equal;
size_t arg_len;

@@ -1769,7 +1756,7 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)

tmp = kstrdup(argv[i], GFP_KERNEL);
if (!tmp)
- goto nomem;
+ return -ENOMEM;

equal = strchr(tmp, '=');
if (equal)
@@ -1790,18 +1777,15 @@ int traceprobe_expand_dentry_args(int argc, const char *argv[], char **buf)
offsetof(struct file, f_path.dentry),
equal ? equal + 1 : tmp);

- kfree(tmp);
+ kfree(no_free_ptr(tmp));
if (ret >= bufsize - used)
- goto nomem;
+ return -ENOMEM;
argv[i] = tmpbuf + used;
used += ret + 1;
}

- *buf = tmpbuf;
+ *buf = no_free_ptr(tmpbuf);
return 0;
-nomem:
- kfree(tmpbuf);
- return -ENOMEM;
}

void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)