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tracing: Check if tracing is enabled in trace_puts()

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commit 3132e107d6 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: 09ae72348e "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>
This commit is contained in:
Steven Rostedt (Red Hat) 2014-01-23 12:27:59 -05:00 • committed by Greg Kroah-Hartman
commit f74bb7400b
1 changed files with 6 additions and 0 deletions
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6
kernel/trace/trace.c
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@ -424,6 +424,9 @@ 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);
@ -464,6 +467,9 @@ 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,