diff options
| author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2014-01-23 12:27:59 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-13 13:47:59 -0800 |
| commit | f74bb7400b79ea730fc5626dc9172d1c236a7498 (patch) | |
| tree | e22fc88ba5a03021c1330b6bf8691fc20392eff2 | |
| parent | fb23eaf401bf37602ff9a222d99980ea4d219765 (diff) | |
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 <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/trace/trace.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b7f5471ae51..6dbdf277c8f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -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, |