Re: [PATCH 0/5][GIT PULL][v2.6.33] tracing: fixes and documentation updates

[Ingo Molnar <mingo@elte.hu>]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> Ingo,
> 
> I found that reading the trace file and the raw_trace_pipe using splice, at 
> the same time could cause a kernel oops. Not a major one, that is, the oops 
> only crashes the user task that is performing the read of the trace file. 
> But still urgent enough to go into 2.6.33.
> 
> The issue is with the iterator that is stored to access multiple reads of 
> the ring buffer without consuming the data. If a user process starts reading 
> the contents of the ring buffer with the iterator, and in the mean time a 
> consuming read is done, then the iterator can become stale and return a 
> bogus entry.
> 
> The first patch fixes the pid to cmdline mapping function to not crash when 
> given a negative pid (which happened when we had a bogus entry).
> 
> The next two patches fix the ring buffer to detect when a consuming
> read is done and to reset the iterator.
> 
> Since I'm pushing these patches up, I've also incuded two
> documentation changes. One of the patches touches a Kconfig file
> but only the help portion of it.
> 
> Please pull the latest tip/tracing/urgent tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/tracing/urgent
> 
> 
> Mike Frysinger (1):
>       tracing/documentation: Cover new frame pointer semantics
> 
> Steven Rostedt (3):
>       tracing: Prevent kernel oops with corrupted buffer
>       ring-buffer: Check if ring buffer iterator has stale data
>       ring-buffer: Check for end of page in iterator
> 
> Yang Hongyang (1):
>       tracing/documentation: Fix a typo in ftrace.txt
> 
> ----
>  Documentation/trace/ftrace-design.txt |   26 +++++++++++++++++++++++---
>  Documentation/trace/ftrace.txt        |    2 +-
>  kernel/trace/Kconfig                  |    4 +---
>  kernel/trace/ring_buffer.c            |   24 +++++++++++++++++++++---
>  kernel/trace/trace.c                  |    5 +++++
>  5 files changed, 51 insertions(+), 10 deletions(-)

Pulled, thanks a lot Steve!

	Ingo