On Mon 2016-02-01 20:17:35, Jessica Yu wrote: > Remove the ftrace module notifier in favor of directly calling > ftrace_module_enable() and ftrace_release_mod() in the module loader. > Hard-coding the function calls directly in the module loader removes > dependence on the module notifier call chain and provides better > visibility and control over what gets called when, which is important > to kernel utilities such as livepatch. > > Signed-off-by: Jessica Yu <[email protected]> > --- > include/linux/ftrace.h | 6 ++++-- > kernel/module.c | 4 ++++ > kernel/trace/ftrace.c | 36 +----------------------------------- > 3 files changed, 9 insertions(+), 37 deletions(-) > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index 81de712..c2b340e 100644 > --- 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 8358f46..b05d466 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -981,6 +981,8 @@ 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 */ > @@ -3295,6 +3297,7 @@ 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; > @@ -3371,6 +3374,7 @@ 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;
Also we need to call ftrace_release_mod() in bug_cleanup: goto target in load_module(). Otherwise, it will stay enabled when, e.g. parse_args() fails. Best Regards, Petr
