Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livep...

Pull livepatching fixes from Jiri Kosina:

 - regression (from 4.4) fix for ordering issue, introduced by an
   earlier ftrace change, that broke live patching of modules.

   The fix replaces the ftrace module notifier by direct call in order
   to make the ordering guaranteed and well-defined.  The patch, from
   Jessica Yu, has been acked both by Steven and Rusty

 - error message fix from Miroslav Benes

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
  ftrace/module: remove ftrace module notifier
  livepatch: change the error message in asm/livepatch.h header files

diff --git a/arch/s390/include/asm/livepatch.h b/arch/s390/include/asm/livepatch.h
index 7aa799134a11754b09ad523a00e54c92a6e1c7a9..a52b6cca873d380adc9bec726cc31816dba5cd6b 100644 (file)
--- a/arch/s390/include/asm/livepatch.h
+++ b/arch/s390/include/asm/livepatch.h
@@ -37,7 +37,7 @@ static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
        regs->psw.addr = ip;
 }
 #else
-#error Live patching support is disabled; check CONFIG_LIVEPATCH
+#error Include linux/livepatch.h, not asm/livepatch.h
 #endif
 
 #endif

diff --git a/arch/x86/include/asm/livepatch.h b/arch/x86/include/asm/livepatch.h
index 19c099afa8613ead6565917f5787deb3df12c9e7..e795f5274217a47cf1713063399675a175d5a4ea 100644 (file)
--- a/arch/x86/include/asm/livepatch.h
+++ b/arch/x86/include/asm/livepatch.h
@@ -41,7 +41,7 @@ static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip)
        regs->ip = ip;
 }
 #else
-#error Live patching support is disabled; check CONFIG_LIVEPATCH
+#error Include linux/livepatch.h, not asm/livepatch.h
 #endif
 
 #endif /* _ASM_X86_LIVEPATCH_H */

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 81de7123959d96d97dd57d41d76289b3a8185920..c2b340e23f62d3240abc6360ab0412a82a12f21a 100644 (file)
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -603,6 +603,7 @@ extern int ftrace_arch_read_dyn_info(char *buf, int size);
 
 extern int skip_trace(unsigned long ip);
 extern void ftrace_module_init(struct module *mod);
+extern void ftrace_module_enable(struct module *mod);
 extern void ftrace_release_mod(struct module *mod);
 
 extern void ftrace_disable_daemon(void);
@@ -612,8 +613,9 @@ static inline int skip_trace(unsigned long ip) { return 0; }
 static inline int ftrace_force_update(void) { return 0; }
 static inline void ftrace_disable_daemon(void) { }
 static inline void ftrace_enable_daemon(void) { }
-static inline void ftrace_release_mod(struct module *mod) {}
-static inline void ftrace_module_init(struct module *mod) {}
+static inline void ftrace_module_init(struct module *mod) { }
+static inline void ftrace_module_enable(struct module *mod) { }
+static inline void ftrace_release_mod(struct module *mod) { }
 static inline __init int register_ftrace_command(struct ftrace_func_command *cmd)
 {
        return -EINVAL;

diff --git a/kernel/module.c b/kernel/module.c
index 9537da37ce87fe28cf11ee97d78bfa17ddc6beb3..794ebe8e878d55cf9a0b94a1ae7a994ac4dec80b 100644 (file)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -984,6 +984,8 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
                mod->exit();
        blocking_notifier_call_chain(&module_notify_list,
                                     MODULE_STATE_GOING, mod);
+       ftrace_release_mod(mod);
+
        async_synchronize_full();
 
        /* Store the name of the last unloaded module for diagnostic purposes */
@@ -3313,6 +3315,7 @@ fail:
        module_put(mod);
        blocking_notifier_call_chain(&module_notify_list,
                                     MODULE_STATE_GOING, mod);
+       ftrace_release_mod(mod);
        free_module(mod);
        wake_up_all(&module_wq);
        return ret;
@@ -3389,6 +3392,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
        mod->state = MODULE_STATE_COMING;
        mutex_unlock(&module_mutex);
 
+       ftrace_module_enable(mod);
        blocking_notifier_call_chain(&module_notify_list,
                                     MODULE_STATE_COMING, mod);
        return 0;

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index eca592f977b260689dc48911f867375b20ad5c8b..57a6eea8469408e7aba78669107eb3a1740362e4 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4961,7 +4961,7 @@ void ftrace_release_mod(struct module *mod)
        mutex_unlock(&ftrace_lock);
 }
 
-static void ftrace_module_enable(struct module *mod)
+void ftrace_module_enable(struct module *mod)
 {
        struct dyn_ftrace *rec;
        struct ftrace_page *pg;
@@ -5038,38 +5038,8 @@ void ftrace_module_init(struct module *mod)
        ftrace_process_locs(mod, mod->ftrace_callsites,
                            mod->ftrace_callsites + mod->num_ftrace_callsites);
 }
-
-static int ftrace_module_notify(struct notifier_block *self,
-                               unsigned long val, void *data)
-{
-       struct module *mod = data;
-
-       switch (val) {
-       case MODULE_STATE_COMING:
-               ftrace_module_enable(mod);
-               break;
-       case MODULE_STATE_GOING:
-               ftrace_release_mod(mod);
-               break;
-       default:
-               break;
-       }
-
-       return 0;
-}
-#else
-static int ftrace_module_notify(struct notifier_block *self,
-                               unsigned long val, void *data)
-{
-       return 0;
-}
 #endif /* CONFIG_MODULES */
 
-struct notifier_block ftrace_module_nb = {
-       .notifier_call = ftrace_module_notify,
-       .priority = INT_MIN,    /* Run after anything that can remove kprobes */
-};
-
 void __init ftrace_init(void)
 {
        extern unsigned long __start_mcount_loc[];
@@ -5098,10 +5068,6 @@ void __init ftrace_init(void)
                                  __start_mcount_loc,
                                  __stop_mcount_loc);
 
-       ret = register_module_notifier(&ftrace_module_nb);
-       if (ret)
-               pr_warning("Failed to register trace ftrace module exit notifier\n");
-
        set_ftrace_early_filters();
 
        return;