From: Steven Rostedt (Red Hat) Date: Thu, 23 Jan 2014 17:27:59 +0000 (-0500) Subject: tracing: Check if tracing is enabled in trace_puts() X-Git-Tag: submit/tizen_common/20140905.094502~855 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8c0b860ecba3c32e8c784bb6840363301f6a1fe3;p=sdk%2Femulator%2Femulator-kernel.git tracing: Check if tracing is enabled in trace_puts() 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d8d9ab4af68c..138077b1a607 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -435,6 +435,9 @@ int __trace_puts(unsigned long ip, const char *str, int size) 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, const char *str) 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,