diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sysctl.c | 2 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 78 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 40 |
3 files changed, 79 insertions, 41 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 706309f9ed84..6ccc60dfbc7a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -634,7 +634,7 @@ static struct ctl_table kern_table[] = { .data = &tracepoint_printk, .maxlen = sizeof(tracepoint_printk), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = tracepoint_printk_sysctl, }, #endif #ifdef CONFIG_KEXEC_CORE diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 490533726b54..725e8b2c453f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -69,6 +69,7 @@ bool __read_mostly tracing_selftest_disabled; /* Pipe tracepoints to printk */ struct trace_iterator *tracepoint_print_iter; int tracepoint_printk; +static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key); /* For tracers that don't implement custom flags */ static struct tracer_opt dummy_tracer_opt[] = { @@ -2116,6 +2117,81 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb, } EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); +static DEFINE_SPINLOCK(tracepoint_iter_lock); +static DEFINE_MUTEX(tracepoint_printk_mutex); + +static void output_printk(struct trace_event_buffer *fbuffer) +{ + struct trace_event_call *event_call; + struct trace_event *event; + unsigned long flags; + struct trace_iterator *iter = tracepoint_print_iter; + + /* We should never get here if iter is NULL */ + if (WARN_ON_ONCE(!iter)) + return; + + event_call = fbuffer->trace_file->event_call; + if (!event_call || !event_call->event.funcs || + !event_call->event.funcs->trace) + return; + + event = &fbuffer->trace_file->event_call->event; + + spin_lock_irqsave(&tracepoint_iter_lock, flags); + trace_seq_init(&iter->seq); + iter->ent = fbuffer->entry; + event_call->event.funcs->trace(iter, 0, event); + trace_seq_putc(&iter->seq, 0); + printk("%s", iter->seq.buffer); + + spin_unlock_irqrestore(&tracepoint_iter_lock, flags); +} + +int tracepoint_printk_sysctl(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + int save_tracepoint_printk; + int ret; + + mutex_lock(&tracepoint_printk_mutex); + save_tracepoint_printk = tracepoint_printk; + + ret = proc_dointvec(table, write, buffer, lenp, ppos); + + /* + * This will force exiting early, as tracepoint_printk + * is always zero when tracepoint_printk_iter is not allocated + */ + if (!tracepoint_print_iter) + tracepoint_printk = 0; + + if (save_tracepoint_printk == tracepoint_printk) + goto out; + + if (tracepoint_printk) + static_key_enable(&tracepoint_printk_key.key); + else + static_key_disable(&tracepoint_printk_key.key); + + out: + mutex_unlock(&tracepoint_printk_mutex); + + return ret; +} + +void trace_event_buffer_commit(struct trace_event_buffer *fbuffer) +{ + if (static_key_false(&tracepoint_printk_key.key)) + output_printk(fbuffer); + + event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer, + fbuffer->event, fbuffer->entry, + fbuffer->flags, fbuffer->pc); +} +EXPORT_SYMBOL_GPL(trace_event_buffer_commit); + void trace_buffer_unlock_commit_regs(struct trace_array *tr, struct ring_buffer *buffer, struct ring_buffer_event *event, @@ -7977,6 +8053,8 @@ void __init trace_init(void) kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL); if (WARN_ON(!tracepoint_print_iter)) tracepoint_printk = 0; + else + static_key_enable(&tracepoint_printk_key.key); } tracer_alloc_buffers(); trace_event_init(); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index ba67ede48822..d35fc2b0d304 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -283,46 +283,6 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer, } EXPORT_SYMBOL_GPL(trace_event_buffer_reserve); -static DEFINE_SPINLOCK(tracepoint_iter_lock); - -static void output_printk(struct trace_event_buffer *fbuffer) -{ - struct trace_event_call *event_call; - struct trace_event *event; - unsigned long flags; - struct trace_iterator *iter = tracepoint_print_iter; - - if (!iter) - return; - - event_call = fbuffer->trace_file->event_call; - if (!event_call || !event_call->event.funcs || - !event_call->event.funcs->trace) - return; - - event = &fbuffer->trace_file->event_call->event; - - spin_lock_irqsave(&tracepoint_iter_lock, flags); - trace_seq_init(&iter->seq); - iter->ent = fbuffer->entry; - event_call->event.funcs->trace(iter, 0, event); - trace_seq_putc(&iter->seq, 0); - printk("%s", iter->seq.buffer); - - spin_unlock_irqrestore(&tracepoint_iter_lock, flags); -} - -void trace_event_buffer_commit(struct trace_event_buffer *fbuffer) -{ - if (tracepoint_printk) - output_printk(fbuffer); - - event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer, - fbuffer->event, fbuffer->entry, - fbuffer->flags, fbuffer->pc); -} -EXPORT_SYMBOL_GPL(trace_event_buffer_commit); - int trace_event_reg(struct trace_event_call *call, enum trace_reg type, void *data) { |