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: firefly_0821_release~176^2~4558^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3132e107d608f8753240d82d61303c500fd515b4;p=firefly-linux-kernel-4.4.55.git tracing: Check if tracing is enabled in trace_puts() 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. Cc: stable@vger.kernel.org # 3.10+ Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing" Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 7857ea9b3b9c..815c878f409b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -455,6 +455,9 @@ 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); @@ -495,6 +498,9 @@ 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,