Ingo, Here's take two of the last patch series I sent. The only difference with this series is that I encapsulate the max_tr reference with the #ifdef CONFIG_TRACER_MAX_TRACE. Other than that, it's the same.
Here's the recap:
The first patch fixes a long standing bug where the changing of
the trace options has absolutely no protection against multiple
changers. Luckily, this is something that requires human (root)
action, and is usually performed by a single individual. But as
scripts are starting to become more active, this bug is bound to
be triggered.
The second patch is a bug where the setting of the overwrite flag
can cause the max and normal buffers to get out of sync. This
is more predomitinant with the 3.9 snapshot feature, but still
has an affect on the latency tracers. Which bring us to the third
patch.
The third patch I found out that disabling overwrite to the buffers
screws with the latency tracers. If the buffer is in produce consumer
mode, the irqsoff tracer and friends wont show any output at all.
This was a bit frustrating to figure out.
Hopefully this time it's good.
Thanks,
-- Steve
Please pull the latest tip/perf/urgent-2 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/perf/urgent-2
Head SHA1: 613f04a0f51e6e68ac6fe571ab79da3c0a5eb4da
Steven Rostedt (Red Hat) (3):
tracing: Protect tracer flags with trace_types_lock
tracing: Keep overwrite in sync between regular and snapshot buffers
tracing: Prevent buffer overwrite disabled for latency tracers
----
kernel/trace/trace.c | 56 +++++++++++++++++++++++++++++--------
kernel/trace/trace.h | 6 ++++
kernel/trace/trace_irqsoff.c | 19 +++++++++----
kernel/trace/trace_sched_wakeup.c | 18 ++++++++----
4 files changed, 78 insertions(+), 21 deletions(-)
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