diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 024d9797646ee1abdfc99e0b12f75576603c9371..b5ef474be858d4278f05e778bf8985ed5636b998 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -9,6 +9,13 @@
# define MCOUNT_ADDR ((unsigned long)(__fentry__))
#define MCOUNT_INSN_SIZE 5 /* sizeof mcount call */
+/* Ignore unused weak functions which will have non zero offsets */
+#ifdef CONFIG_HAVE_FENTRY
+# include <asm/ibt.h>
+/* Add offset for endbr64 if IBT enabled */
+# define FTRACE_MCOUNT_MAX_OFFSET ENDBR_INSN_SIZE
+#endif
+
#ifdef CONFIG_DYNAMIC_FTRACE
#define ARCH_SUPPORTS_FTRACE_OPS 1
#endif
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d653ef4febc5c30c86b524d4dfe5bcdbfadee464..c5088c76a108f911330a0cb5e0a5c4d6aa2026c8 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -45,6 +45,8 @@
#include "trace_output.h"
#include "trace_stat.h"
+#define FTRACE_INVALID_FUNCTION "__ftrace_invalid_address__"
+
#define FTRACE_WARN_ON(cond) \
({ \
int ___r = cond; \
@@ -3654,6 +3656,105 @@ static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
seq_printf(m, " ->%pS", ptr);
}
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+/*
+ * Weak functions can still have an mcount/fentry that is saved in
+ * the __mcount_loc section. These can be detected by having a
+ * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
+ * symbol found by kallsyms is not the function that the mcount/fentry
+ * is part of. The offset is much greater in these cases.
+ *
+ * Test the record to make sure that the ip points to a valid kallsyms
+ * and if not, mark it disabled.
+ */
+static int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+ char str[KSYM_SYMBOL_LEN];
+ unsigned long offset;
+ const char *ret;
+
+ ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
+
+ /* Weak functions can cause invalid addresses */
+ if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+ rec->flags |= FTRACE_FL_DISABLED;
+ return 0;
+ }
+ return 1;
+}
+
+static struct workqueue_struct *ftrace_check_wq __initdata;
+static struct work_struct ftrace_check_work __initdata;
+
+/*
+ * Scan all the mcount/fentry entries to make sure they are valid.
+ */
+static __init void ftrace_check_work_func(struct work_struct *work)
+{
+ struct ftrace_page *pg;
+ struct dyn_ftrace *rec;
+
+ mutex_lock(&ftrace_lock);
+ do_for_each_ftrace_rec(pg, rec) {
+ test_for_valid_rec(rec);
+ } while_for_each_ftrace_rec();
+ mutex_unlock(&ftrace_lock);
+}
+
+static int __init ftrace_check_for_weak_functions(void)
+{
+ INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
+
+ ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
+
+ queue_work(ftrace_check_wq, &ftrace_check_work);
+ return 0;
+}
+
+static int __init ftrace_check_sync(void)
+{
+ /* Make sure the ftrace_check updates are finished */
+ if (ftrace_check_wq)
+ destroy_workqueue(ftrace_check_wq);
+ return 0;
+}
+
+late_initcall_sync(ftrace_check_sync);
+subsys_initcall(ftrace_check_for_weak_functions);
+
+static int print_rec(struct seq_file *m, unsigned long ip)
+{
+ unsigned long offset;
+ char str[KSYM_SYMBOL_LEN];
+ char *modname;
+ const char *ret;
+
+ ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
+ /* Weak functions can cause invalid addresses */
+ if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
+ snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
+ FTRACE_INVALID_FUNCTION, offset);
+ ret = NULL;
+ }
+
+ seq_puts(m, str);
+ if (modname)
+ seq_printf(m, " [%s]", modname);
+ return ret == NULL ? -1 : 0;
+}
+#else
+static inline int test_for_valid_rec(struct dyn_ftrace *rec)
+{
+ return 1;
+}
+
+static inline int print_rec(struct seq_file *m, unsigned long ip)
+{
+ seq_printf(m, "%ps", (void *)ip);
+ return 0;
+}
+#endif
+
static int t_show(struct seq_file *m, void *v)
{
struct ftrace_iterator *iter = m->private;
@@ -3678,7 +3779,13 @@ static int t_show(struct seq_file *m, void *v)
if (!rec)
return 0;
- seq_printf(m, "%ps", (void *)rec->ip);
+ if (print_rec(m, rec->ip)) {
+ /* This should only happen when a rec is disabled */
+ WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
+ seq_putc(m, '\n');
+ return 0;
+ }
+
if (iter->flags & FTRACE_ITER_ENABLED) {
struct ftrace_ops *ops;
@@ -3996,6 +4103,24 @@ add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
return 0;
}
+#ifdef FTRACE_MCOUNT_MAX_OFFSET
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+ unsigned long offset;
+
+ kallsyms_lookup(ip, NULL, &offset, modname, str);
+ if (offset > FTRACE_MCOUNT_MAX_OFFSET)
+ return -1;
+ return 0;
+}
+#else
+static int lookup_ip(unsigned long ip, char **modname, char *str)
+{
+ kallsyms_lookup(ip, NULL, NULL, modname, str);
+ return 0;
+}
+#endif
+
static int
ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
struct ftrace_glob *mod_g, int exclude_mod)
@@ -4003,7 +4128,12 @@ ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
char str[KSYM_SYMBOL_LEN];
char *modname;
- kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
+ if (lookup_ip(rec->ip, &modname, str)) {
+ /* This should only happen when a rec is disabled */
+ WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
+ !(rec->flags & FTRACE_FL_DISABLED));
+ return 0;
+ }
if (mod_g) {
int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
@@ -6819,6 +6949,13 @@ void ftrace_module_enable(struct module *mod)
!within_module_init(rec->ip, mod))
break;
+ /* Weak functions should still be ignored */
+ if (!test_for_valid_rec(rec)) {
+ /* Clear all other flags. Should not be enabled anyway */
+ rec->flags = FTRACE_FL_DISABLED;
+ continue;
+ }
+
cnt = 0;
/*