tracing: Check if tracing is enabled in trace_puts() (3132e107) · Commits · 戴 / test

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: "tracing: Add trace_puts() for even faster trace_printk() tracing" Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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,

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