While auditing all module notifiers I noticed a whole bunch of fail wrt the return value. Notifiers have a 'special' return semantics.
Cc: Robert Richter <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Alexei Starovoitov <[email protected]> Cc: Daniel Borkmann <[email protected]> Cc: Martin KaFai Lau <[email protected]> Cc: Song Liu <[email protected]> Cc: Yonghong Song <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: "Paul E. McKenney" <[email protected]> Cc: "Joel Fernandes (Google)" <[email protected]> Cc: Ard Biesheuvel <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Peter Zijlstra (Intel) <[email protected]> --- drivers/oprofile/buffer_sync.c | 4 ++-- kernel/module.c | 9 +++++---- kernel/trace/bpf_trace.c | 8 ++++++-- kernel/trace/trace.c | 2 +- kernel/trace/trace_events.c | 2 +- kernel/trace/trace_printk.c | 4 ++-- kernel/tracepoint.c | 2 +- 7 files changed, 18 insertions(+), 13 deletions(-) --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -116,7 +116,7 @@ module_load_notify(struct notifier_block { #ifdef CONFIG_MODULES if (val != MODULE_STATE_COMING) - return 0; + return NOTIFY_DONE; /* FIXME: should we process all CPU buffers ? */ mutex_lock(&buffer_mutex); @@ -124,7 +124,7 @@ module_load_notify(struct notifier_block add_event_entry(MODULE_LOADED_CODE); mutex_unlock(&buffer_mutex); #endif - return 0; + return NOTIFY_OK; } --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1302,10 +1302,11 @@ static int bpf_event_notify(struct notif { struct bpf_trace_module *btm, *tmp; struct module *mod = module; + int ret = 0; if (mod->num_bpf_raw_events == 0 || (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING)) - return 0; + goto out; mutex_lock(&bpf_module_mutex); @@ -1315,6 +1316,8 @@ static int bpf_event_notify(struct notif if (btm) { btm->module = module; list_add(&btm->list, &bpf_trace_modules); + } else { + ret = -ENOMEM; } break; case MODULE_STATE_GOING: @@ -1330,7 +1333,8 @@ static int bpf_event_notify(struct notif mutex_unlock(&bpf_module_mutex); - return 0; +out: + return notifier_from_errno(ret); } static struct notifier_block bpf_module_nb = { --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8685,7 +8685,7 @@ static int trace_module_notify(struct no break; } - return 0; + return NOTIFY_OK; } static struct notifier_block trace_module_nb = { --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2450,7 +2450,7 @@ static int trace_module_notify(struct no mutex_unlock(&trace_types_lock); mutex_unlock(&event_mutex); - return 0; + return NOTIFY_OK; } static struct notifier_block trace_module_nb = { --- a/kernel/trace/trace_printk.c +++ b/kernel/trace/trace_printk.c @@ -95,7 +95,7 @@ static int module_trace_bprintk_format_n if (val == MODULE_STATE_COMING) hold_module_trace_bprintk_format(start, end); } - return 0; + return NOTIFY_OK; } /* @@ -173,7 +173,7 @@ __init static int module_trace_bprintk_format_notify(struct notifier_block *self, unsigned long val, void *data) { - return 0; + return NOTIFY_OK; } static inline const char ** find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos) --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -538,7 +538,7 @@ static int tracepoint_module_notify(stru case MODULE_STATE_UNFORMED: break; } - return ret; + return notifier_from_errno(ret); } static struct notifier_block tracepoint_module_nb = {
