Probe fixes for 6.5-rc3:

- probe-events: Fix to add NULL check for some BTF API calls which can
   return error code and NULL.
 
 - ftrace selftests: Fix to check fprobe and kprobe event correctly. This
   fixes a miss condition of the test command.
 
 - kprobes: Prohibit probing on the function which starts from "__cfi_"
   and "__pfx_" since those are auto generated for kernel CFI and not
   executed.
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Merge tag 'probes-fixes-v6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probe fixes from Masami Hiramatsu:

 - probe-events: add NULL check for some BTF API calls which can return
   error code and NULL.

 - ftrace selftests: check fprobe and kprobe event correctly. This fixes
   a miss condition of the test command.

 - kprobes: do not allow probing functions that start with "__cfi_" or
   "__pfx_" since those are auto generated for kernel CFI and not
   executed.

* tag 'probes-fixes-v6.5-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  kprobes: Prohibit probing on CFI preamble symbol
  selftests/ftrace: Fix to check fprobe event eneblement
  tracing/probes: Fix to add NULL check for BTF APIs

kernel/kprobes.c

@@ -1545,6 +1545,17 @@ static int check_ftrace_location(struct kprobe *p)
 	return 0;
 }
 
+static bool is_cfi_preamble_symbol(unsigned long addr)
+{
+	char symbuf[KSYM_NAME_LEN];
+
+	if (lookup_symbol_name(addr, symbuf))
+		return false;
+
+	return str_has_prefix("__cfi_", symbuf) ||
+		str_has_prefix("__pfx_", symbuf);
+}
+
 static int check_kprobe_address_safe(struct kprobe *p,
 				     struct module **probed_mod)
 {
@@ -1563,7 +1574,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
 	    within_kprobe_blacklist((unsigned long) p->addr) ||
 	    jump_label_text_reserved(p->addr, p->addr) ||
 	    static_call_text_reserved(p->addr, p->addr) ||
-	    find_bug((unsigned long)p->addr)) {
+	    find_bug((unsigned long)p->addr) ||
+	    is_cfi_preamble_symbol((unsigned long)p->addr)) {
 		ret = -EINVAL;
 		goto out;
 	}

kernel/trace/trace_probe.c

@@ -386,12 +386,12 @@ static const struct btf_type *find_btf_func_proto(const char *funcname)
 
 	/* Get BTF_KIND_FUNC type */
 	t = btf_type_by_id(btf, id);
-	if (!btf_type_is_func(t))
+	if (!t || !btf_type_is_func(t))
 		return ERR_PTR(-ENOENT);
 
 	/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
 	t = btf_type_by_id(btf, t->type);
-	if (!btf_type_is_func_proto(t))
+	if (!t || !btf_type_is_func_proto(t))
 		return ERR_PTR(-ENOENT);
 
 	return t;
@@ -443,7 +443,7 @@ static int parse_btf_arg(const char *varname, struct fetch_insn *code,
 	if (!ctx->params) {
 		params = find_btf_func_param(ctx->funcname, &ctx->nr_params,
 					     ctx->flags & TPARG_FL_TPOINT);
-		if (IS_ERR(params)) {
+		if (IS_ERR_OR_NULL(params)) {
 			trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
 			return PTR_ERR(params);
 		}
@@ -1273,7 +1273,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[],
 
 	params = find_btf_func_param(ctx->funcname, &nr_params,
 				     ctx->flags & TPARG_FL_TPOINT);
-	if (IS_ERR(params)) {
+	if (IS_ERR_OR_NULL(params)) {
 		if (args_idx != -1) {
 			/* $arg* requires BTF info */
 			trace_probe_log_err(0, NOSUP_BTFARG);

tools/testing/selftests/ftrace/test.d/dynevent/add_remove_btfarg.tc

@@ -13,7 +13,7 @@ if grep -qF "f[:[<group>/][<event>]] <func-name>[%return] [<args>]" README ; the
   FPROBES=yes
 fi
 
-if [ -z "$KPROBES" -a "$FPROBES" ] ; then
+if [ -z "$KPROBES" -a -z "$FPROBES" ] ; then
   exit_unsupported
 fi