linux-toradex.git/kernel/trace, branch v3.16-rc5

tracing: Remove ftrace_stop/start() from reading the trace file

2014-07-01T16:45:54+00:00

Disabling reading and writing to the trace file should not be able to
disable all function tracing callbacks. There's other users today
(like kprobes and perf). Reading a trace file should not stop those
from happening.

Cc: stable@vger.kernel.org # 3.0+
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()

2014-06-30T17:22:33+00:00

The usage of uprobe_buffer_enable() added by dcad1a20 is very wrong,

1. uprobe_buffer_enable() and uprobe_buffer_disable() are not balanced,
   _enable() should be called only if !enabled.

2. If uprobe_buffer_enable() fails probe_event_enable() should clear
   tp.flags and free event_file_link.

3. If uprobe_register() fails it should do uprobe_buffer_disable().

Link: http://lkml.kernel.org/p/20140627170146.GA18332@redhat.com

Acked-by: Namhyung Kim 
Acked-by: Srikar Dronamraju 
Reviewed-by: Masami Hiramatsu 
Fixes: dcad1a204f72 "tracing/uprobes: Fetch args before reserving a ring buffer"
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing/uprobes: Kill the bogus UPROBE_HANDLER_REMOVE code in uprobe_dispatcher()

2014-06-30T17:22:23+00:00

I do not know why dd9fa555d7bb "tracing/uprobes: Move argument fetching
to uprobe_dispatcher()" added the UPROBE_HANDLER_REMOVE, but it looks
wrong.

OK, perhaps it makes sense to avoid store_trace_args() if the tracee is
nacked by uprobe_perf_filter(). But then we should kill the same code
in uprobe_perf_func() and unify the TRACE/PROFILE filtering (we need to
do this anyway to mix perf/ftrace). Until then this code actually adds
the pessimization because uprobe_perf_filter() will be called twice and
return T in likely case.

Link: http://lkml.kernel.org/p/20140627170143.GA18329@redhat.com

Acked-by: Namhyung Kim 
Acked-by: Srikar Dronamraju 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing/uprobes: Revert "Support mix of ftrace and perf"

2014-06-30T17:21:58+00:00

This reverts commit 43fe98913c9f67e3b523615ee3316f9520a623e0.

This patch is very wrong. Firstly, this change leads to unbalanced
uprobe_unregister(). Just for example,

	# perf probe -x /lib/libc.so.6 syscall
	# echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable
	# perf record -e probe_libc:syscall whatever

after that uprobe is dead (unregistered) but the user of ftrace/perf
can't know this, and it looks as if nobody hits this probe.

This would be easy to fix, but there are other reasons why it is not
simple to mix ftrace and perf. If nothing else, they can't share the
same ->consumer.filter. This is fixable too, but probably we need to
fix the poorly designed uprobe_register() interface first. At least
"register" and "apply" should be clearly separated.

Link: http://lkml.kernel.org/p/20140627170136.GA18319@redhat.com

Cc: Tom Zanussi 
Cc: "zhangwei(Jovi)" 
Cc: stable@vger.kernel.org # v3.14
Acked-by: Namhyung Kim 
Acked-by: Srikar Dronamraju 
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

Merge tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-06-13T04:07:25+00:00

Pull tracing cleanups and bugfixes from Steven Rostedt:
 "One bug fix that goes back to 3.10.  Accessing a non existent buffer
  if "possible cpus" is greater than actual CPUs (including offline
  CPUs).

  Namhyung Kim did some reviews of the patches I sent this merge window
  and found a memory leak and had a few clean ups"

* tag 'trace-3.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix check of ftrace_trace_arrays list_empty() check
  tracing: Fix leak of per cpu max data in instances
  tracing: Cleanup saved_cmdlines_size changes
  ring-buffer: Check if buffer exists before polling

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-06-13T02:18:49+00:00

Pull more perf updates from Ingo Molnar:
 "A second round of perf updates:

   - wide reaching kprobes sanitization and robustization, with the hope
     of fixing all 'probe this function crashes the kernel' bugs, by
     Masami Hiramatsu.

   - uprobes updates from Oleg Nesterov: tmpfs support, corner case
     fixes and robustization work.

   - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo
     et al:
        * Add support to accumulate hist periods (Namhyung Kim)
        * various fixes, refactorings and enhancements"

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
  perf: Differentiate exec() and non-exec() comm events
  perf: Fix perf_event_comm() vs. exec() assumption
  uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates
  perf/documentation: Add description for conditional branch filter
  perf/x86: Add conditional branch filtering support
  perf/tool: Add conditional branch filter 'cond' to perf record
  perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND'
  uprobes: Teach copy_insn() to support tmpfs
  uprobes: Shift ->readpage check from __copy_insn() to uprobe_register()
  perf/x86: Use common PMU interrupt disabled code
  perf/ARM: Use common PMU interrupt disabled code
  perf: Disable sampled events if no PMU interrupt
  perf: Fix use after free in perf_remove_from_context()
  perf tools: Fix 'make help' message error
  perf record: Fix poll return value propagation
  perf tools: Move elide bool into perf_hpp_fmt struct
  perf tools: Remove elide setup for SORT_MODE__MEMORY mode
  perf tools: Fix "==" into "=" in ui_browser__warning assignment
  perf tools: Allow overriding sysfs and proc finding with env var
  perf tools: Consider header files outside perf directory in tags target
  ...

tracing: Fix check of ftrace_trace_arrays list_empty() check

2014-06-10T17:53:50+00:00

The check that tests if ftrace_trace_arrays is empty in
top_trace_array(), uses the .prev pointer:

  if (list_empty(ftrace_trace_arrays.prev))

instead of testing the variable itself:

  if (list_empty(&ftrace_trace_arrays))

Although it is technically correct, it is awkward and confusing.
Use the proper method.

Link: http://lkml.kernel.org/r/87oay1bas8.fsf@sejong.aot.lge.com

Reported-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing: Fix leak of per cpu max data in instances

2014-06-10T16:06:30+00:00

The freeing of an instance, if max data is configured, there will be
per cpu data structures created. But these are not freed when the instance
is deleted, which causes a memory leak.

A new helper function is added that frees the individual buffers within a
trace array, instead of duplicating the code. This way changes made for one
are applied to the other (normal buffer vs max buffer).

Link: http://lkml.kernel.org/r/87k38pbake.fsf@sejong.aot.lge.com

Reported-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

tracing: Cleanup saved_cmdlines_size changes

2014-06-10T13:51:10+00:00

The recent addition of saved_cmdlines_size file had some remaining
(minor - mostly coding style) issues.  Fix them by passing pointer
name to sizeof() and using scnprintf().

Link: http://lkml.kernel.org/p/1402384295-23680-1-git-send-email-namhyung@kernel.org

Cc: Namhyung Kim 
Cc: Ingo Molnar 
Cc: Yoshihiro YUNOMAE 
Signed-off-by: Namhyung Kim 
Signed-off-by: Steven Rostedt

ring-buffer: Check if buffer exists before polling

2014-06-10T13:46:00+00:00

The per_cpu buffers are created one per possible CPU. But these do
not mean that those CPUs are online, nor do they even exist.

With the addition of the ring buffer polling, it assumes that the
caller polls on an existing buffer. But this is not the case if
the user reads trace_pipe from a CPU that does not exist, and this
causes the kernel to crash.

Simple fix is to check the cpu against buffer bitmask against to see
if the buffer was allocated or not and return -ENODEV if it is
not.

More updates were done to pass the -ENODEV back up to userspace.

Link: http://lkml.kernel.org/r/5393DB61.6060707@oracle.com

Reported-by: Sasha Levin 
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Steven Rostedt