1 files changed, 51 insertions, 41 deletions

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index bac752f0cfb5..ee7b5a0bb9f8 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -23,9 +23,6 @@ static int syscall_exit_register(struct ftrace_event_call *event,
 static int syscall_enter_define_fields(struct ftrace_event_call *call);
 static int syscall_exit_define_fields(struct ftrace_event_call *call);
 
-/* All syscall exit events have the same fields */
-static LIST_HEAD(syscall_exit_fields);
-
 static struct list_head *
 syscall_get_enter_fields(struct ftrace_event_call *call)
 {
@@ -34,61 +31,66 @@ syscall_get_enter_fields(struct ftrace_event_call *call)
         return &entry->enter_fields;
 }
 
-static struct list_head *
-syscall_get_exit_fields(struct ftrace_event_call *call)
-{
-        return &syscall_exit_fields;
-}
-
 struct trace_event_functions enter_syscall_print_funcs = {
-        .trace                  = print_syscall_enter,
+        .trace          = print_syscall_enter,
 };
 
 struct trace_event_functions exit_syscall_print_funcs = {
-        .trace                  = print_syscall_exit,
+        .trace          = print_syscall_exit,
 };
 
 struct ftrace_event_class event_class_syscall_enter = {
-        .system                 = "syscalls",
-        .reg                    = syscall_enter_register,
-        .define_fields          = syscall_enter_define_fields,
-        .get_fields             = syscall_get_enter_fields,
-        .raw_init               = init_syscall_trace,
+        .system         = "syscalls",
+        .reg            = syscall_enter_register,
+        .define_fields  = syscall_enter_define_fields,
+        .get_fields     = syscall_get_enter_fields,
+        .raw_init       = init_syscall_trace,
 };
 
 struct ftrace_event_class event_class_syscall_exit = {
-        .system                 = "syscalls",
-        .reg                    = syscall_exit_register,
-        .define_fields          = syscall_exit_define_fields,
-        .get_fields             = syscall_get_exit_fields,
-        .raw_init               = init_syscall_trace,
+        .system         = "syscalls",
+        .reg            = syscall_exit_register,
+        .define_fields  = syscall_exit_define_fields,
+        .fields         = LIST_HEAD_INIT(event_class_syscall_exit.fields),
+        .raw_init       = init_syscall_trace,
 };
 
-extern unsigned long __start_syscalls_metadata[];
-extern unsigned long __stop_syscalls_metadata[];
+extern struct syscall_metadata *__start_syscalls_metadata[];
+extern struct syscall_metadata *__stop_syscalls_metadata[];
 
 static struct syscall_metadata **syscalls_metadata;
 
-static struct syscall_metadata *find_syscall_meta(unsigned long syscall)
+#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
+static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
+{
+        /*
+         * Only compare after the "sys" prefix. Archs that use
+         * syscall wrappers may have syscalls symbols aliases prefixed
+         * with "SyS" instead of "sys", leading to an unwanted
+         * mismatch.
+         */
+        return !strcmp(sym + 3, name + 3);
+}
+#endif
+
+static __init struct syscall_metadata *
+find_syscall_meta(unsigned long syscall)
 {
-        struct syscall_metadata *start;
-        struct syscall_metadata *stop;
+        struct syscall_metadata **start;
+        struct syscall_metadata **stop;
         char str[KSYM_SYMBOL_LEN];
 
 
-        start = (struct syscall_metadata *)__start_syscalls_metadata;
-        stop = (struct syscall_metadata *)__stop_syscalls_metadata;
+        start = __start_syscalls_metadata;
+        stop = __stop_syscalls_metadata;
         kallsyms_lookup(syscall, NULL, NULL, NULL, str);
 
+        if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
+                return NULL;
+
         for ( ; start < stop; start++) {
-                /*
-                 * Only compare after the "sys" prefix. Archs that use
-                 * syscall wrappers may have syscalls symbols aliases prefixed
-                 * with "SyS" instead of "sys", leading to an unwanted
-                 * mismatch.
-                 */
-                if (start->name && !strcmp(start->name + 3, str + 3))
-                        return start;
+                if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
+                        return *start;
         }
         return NULL;
 }
@@ -367,7 +369,7 @@ int reg_event_syscall_enter(struct ftrace_event_call *call)
         int num;
 
         num = ((struct syscall_metadata *)call->data)->syscall_nr;
-        if (num < 0 || num >= NR_syscalls)
+        if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
                 return -ENOSYS;
         mutex_lock(&syscall_trace_lock);
         if (!sys_refcount_enter)
@@ -385,7 +387,7 @@ void unreg_event_syscall_enter(struct ftrace_event_call *call)
         int num;
 
         num = ((struct syscall_metadata *)call->data)->syscall_nr;
-        if (num < 0 || num >= NR_syscalls)
+        if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
                 return;
         mutex_lock(&syscall_trace_lock);
         sys_refcount_enter--;
@@ -401,7 +403,7 @@ int reg_event_syscall_exit(struct ftrace_event_call *call)
         int num;
 
         num = ((struct syscall_metadata *)call->data)->syscall_nr;
-        if (num < 0 || num >= NR_syscalls)
+        if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
                 return -ENOSYS;
         mutex_lock(&syscall_trace_lock);
         if (!sys_refcount_exit)
@@ -419,7 +421,7 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call)
         int num;
 
         num = ((struct syscall_metadata *)call->data)->syscall_nr;
-        if (num < 0 || num >= NR_syscalls)
+        if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
                 return;
         mutex_lock(&syscall_trace_lock);
         sys_refcount_exit--;
@@ -432,6 +434,14 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call)
 int init_syscall_trace(struct ftrace_event_call *call)
 {
         int id;
+        int num;
+
+        num = ((struct syscall_metadata *)call->data)->syscall_nr;
+        if (num < 0 || num >= NR_syscalls) {
+                pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
+                                ((struct syscall_metadata *)call->data)->name);
+                return -ENOSYS;
+        }
 
         if (set_syscall_print_fmt(call) < 0)
                 return -ENOMEM;
@@ -446,7 +456,7 @@ int init_syscall_trace(struct ftrace_event_call *call)
         return id;
 }
 
-unsigned long __init arch_syscall_addr(int nr)
+unsigned long __init __weak arch_syscall_addr(int nr)
 {
         return (unsigned long)sys_call_table[nr];
 }