Merge tag 'probes-fixes-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - Reject $arg0 during meta-argument expansion to prevent negative index
   calculation and out-of-bounds reading of traceprobe parameters

 - Roll back on enable_trace_fprobe() failure

   Add a rollback cleanup path when __register_trace_fprobe() fails
   partway through to unregister registered probes and clear flags or
   file links

 - Fix module reference count leak on error in register_fprobe()

   Ensure the module_put() cleanup loop still runs even when
   get_ips_from_filter() returns an error, preventing module
   reference count leaks

* tag 'probes-fixes-v7.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fprobe: Fix module reference count leak on error in register_fprobe()
  tracing/fprobe: Roll back on enable_trace_fprobe() failure
  tracing/probes: Reject $arg0 in meta argument expansion

3 files changed, 18 insertions, 6 deletions

diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index f215990b9061..f681015413b8 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -961,10 +961,8 @@ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter
 		return -ENOMEM;
 
 	ret = get_ips_from_filter(filter, notfilter, addrs, mods, num);
-	if (ret < 0)
-		return ret;
-
-	ret = register_fprobe_ips(fp, addrs, ret);
+	if (ret >= 0)
+		ret = register_fprobe_ips(fp, addrs, ret);
 
 	for (int i = 0; i < num; i++) {
 		if (mods[i])
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 9f5f08c0e7c2..3120403a5b60 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -1481,11 +1481,21 @@ static int enable_trace_fprobe(struct trace_event_call *call,
 		list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list) {
 			ret = __register_trace_fprobe(tf);
 			if (ret < 0)
-				return ret;
+				goto err;
 		}
 	}
 
 	return 0;
+
+err:
+	/* Failed to enable one of them. Roll back all */
+	list_for_each_entry(tf, trace_probe_probe_list(tp), tp.list)
+		__unregister_trace_fprobe(tf);
+	if (file)
+		trace_probe_remove_file(tp, file);
+	else
+		trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
+	return ret;
 }
 
 /*
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 506e6037e163..c8fd9b946f44 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1901,7 +1901,11 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
 				trace_probe_log_err(0, BAD_VAR);
 				return ERR_PTR(-ENOENT);
 			}
-			/* Note: $argN starts from $arg1 */
+			/* Note: $argN starts from $arg1, so $arg0 is invalid. */
+			if (n == 0) {
+				trace_probe_log_err(0, BAD_ARG_NUM);
+				return ERR_PTR(-EINVAL);
+			}
 			ret = sprint_nth_btf_arg(n - 1, type, buf + used,
 						 bufsize - used, ctx);
 			if (ret < 0)