This is a note to let you know that I've just added the patch titled
tracing: Check if tracing is enabled in trace_puts()
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tracing-check-if-tracing-is-enabled-in-trace_puts.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3132e107d608f8753240d82d61303c500fd515b4 Mon Sep 17 00:00:00 2001
From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
Date: Thu, 23 Jan 2014 12:27:59 -0500
Subject: tracing: Check if tracing is enabled in trace_puts()
From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
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@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/trace/trace.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -455,6 +455,9 @@ int __trace_puts(unsigned long ip, const
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, cons
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,
Patches currently in stable-queue which might be from rostedt@xxxxxxxxxxx are
queue-3.13/ftrace-have-function-graph-only-trace-based-on-global_ops-filters.patch
queue-3.13/ftrace-fix-synchronization-location-disabling-and-freeing-ftrace_ops.patch
queue-3.13/tracing-check-if-tracing-is-enabled-in-trace_puts.patch
queue-3.13/tracing-have-trace-buffer-point-back-to-trace_array.patch
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