| From 3132e107d608f8753240d82d61303c500fd515b4 Mon Sep 17 00:00:00 2001 |
| From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> |
| Date: Thu, 23 Jan 2014 12:27:59 -0500 |
| Subject: tracing: Check if tracing is enabled in trace_puts() |
| |
| From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org> |
| |
| commit 3132e107d608f8753240d82d61303c500fd515b4 upstream. |
| |
| If trace_puts() is used very early in boot up, it can crash the machine |
| if it is called before the ring buffer is allocated. If a trace_printk() |
| is used with no arguments, then it will be converted into a trace_puts() |
| and suffer the same fate. |
| |
| Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing" |
| Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/trace/trace.c | 6 ++++++ |
| 1 file changed, 6 insertions(+) |
| |
| --- a/kernel/trace/trace.c |
| +++ b/kernel/trace/trace.c |
| @@ -435,6 +435,9 @@ int __trace_puts(unsigned long ip, const |
| unsigned long irq_flags; |
| int alloc; |
| |
| + if (unlikely(tracing_selftest_running || tracing_disabled)) |
| + return 0; |
| + |
| alloc = sizeof(*entry) + size + 2; /* possible \n added */ |
| |
| local_save_flags(irq_flags); |
| @@ -475,6 +478,9 @@ int __trace_bputs(unsigned long ip, cons |
| unsigned long irq_flags; |
| int size = sizeof(struct bputs_entry); |
| |
| + if (unlikely(tracing_selftest_running || tracing_disabled)) |
| + return 0; |
| + |
| local_save_flags(irq_flags); |
| buffer = global_trace.trace_buffer.buffer; |
| event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, |
