linux.git/kernel/trace, branch v3.10-rc4

ring-buffer: Do not poll non allocated cpu buffers

2013-05-28T14:53:20+00:00

The tracing infrastructure sets up for possible CPUs, but it uses
the ring buffer polling, it is possible to call the ring buffer
polling code with a CPU that hasn't been allocated. This will cause
a kernel oops when it access a ring buffer cpu buffer that is part
of the possible cpus but hasn't been allocated yet as the CPU has never
been online.

Reported-by: Mauro Carvalho Chehab 
Tested-by: Mauro Carvalho Chehab 
Signed-off-by: Steven Rostedt

tracing: Fix crash when ftrace=nop on the kernel command line

2013-05-23T15:57:25+00:00

If ftrace= is on the kernel command line, when that tracer is
registered, it will be initiated by tracing_set_tracer() to execute that
tracer.

The nop tracer is just a stub tracer that is used to have no tracer
enabled. It is assigned at early bootup as it is the default tracer.

But if ftrace=nop is on the kernel command line, the registering of the
nop tracer will call tracing_set_tracer() which will try to execute
the nop tracer. But it expects tr->current_trace to be assigned something
as it usually is assigned to the nop tracer. As it hasn't been assigned
to anything yet, it causes the system to crash.

The simple fix is to move the tr->current_trace = nop before registering
the nop tracer. The functionality is still the same as the nop tracer
doesn't do anything anyway.

Reported-by: Peter Zijlstra 
Signed-off-by: Steven Rostedt

tracing: Return -EBUSY when event_enable_func() fails to get module

2013-05-16T15:01:16+00:00

Since try_module_get() returns false( = 0) when it fails to
pindown a module, event_enable_func() returns 0 which means
"succeed". This can cause a kernel panic when the entry
is removed, because the event is already released.

This fixes the bug by returning -EBUSY, because the reason
why it fails is that the module is being removed at that time.

Link: http://lkml.kernel.org/r/20130516114848.13508.97899.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju 
Cc: Oleg Nesterov 
Cc: Tom Zanussi 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing/kprobes: Make print_*probe_event static

2013-05-15T17:50:24+00:00

According to sparse warning, print_*probe_event static because
those functions are not directly called from outside.

Link: http://lkml.kernel.org/r/20130513115839.6545.83067.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju 
Cc: Oleg Nesterov 
Cc: Tom Zanussi 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing/kprobes: Fix a sparse warning for incorrect type in assignment

2013-05-15T17:50:23+00:00

Fix a sparse warning about the rcu operated pointer is
defined without __rcu address space.

Link: http://lkml.kernel.org/r/20130513115837.6545.23322.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju 
Cc: Oleg Nesterov 
Cc: Tom Zanussi 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing/kprobes: Use rcu_dereference_raw for tp->files

2013-05-15T17:50:22+00:00

Use rcu_dereference_raw() for accessing tp->files. Because the
write-side uses rcu_assign_pointer() for memory barrier,
the read-side also has to use rcu_dereference_raw() with
read memory barrier.

Link: http://lkml.kernel.org/r/20130513115834.6545.17022.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju 
Cc: Oleg Nesterov 
Cc: Tom Zanussi 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing: Fix leaks of filter preds

2013-05-15T17:49:18+00:00

Special preds are created when folding a series of preds that
can be done in serial. These are allocated in an ops field of
the pred structure. But they were never freed, causing memory
leaks.

This was discovered using the kmemleak checker:

unreferenced object 0xffff8800797fd5e0 (size 32):
  comm "swapper/0", pid 1, jiffies 4294690605 (age 104.608s)
  hex dump (first 32 bytes):
    00 00 01 00 03 00 05 00 07 00 09 00 0b 00 0d 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [] kmemleak_alloc+0x73/0x98
    [] kmemleak_alloc_recursive.constprop.42+0x16/0x18
    [] __kmalloc+0xd7/0x125
    [] kcalloc.constprop.24+0x2d/0x2f
    [] fold_pred_tree_cb+0xa9/0xf4
    [] walk_pred_tree+0x47/0xcc
    [] replace_preds.isra.20+0x6f8/0x72f
    [] create_filter+0x4e/0x8b
    [] ftrace_test_event_filter+0x5a/0x155
    [] do_one_initcall+0xa0/0x137
    [] kernel_init_freeable+0x14d/0x1dc
    [] kernel_init+0xe/0xdb
    [] ret_from_fork+0x7c/0xb0
    [] 0xffffffffffffffff

Cc: Tom Zanussi 
Cc: stable@vger.kernel.org # 2.6.39+
Signed-off-by: Steven Rostedt

Merge tag 'trace-fixes-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2013-05-12T00:04:59+00:00

Pull tracing/kprobes update from Steven Rostedt:
 "The majority of these changes are from Masami Hiramatsu bringing
  kprobes up to par with the latest changes to ftrace (multi buffering
  and the new function probes).

  He also discovered and fixed some bugs in doing so.  When pulling in
  his patches, I also found a few minor bugs as well and fixed them.

  This also includes a compile fix for some archs that select the ring
  buffer but not tracing.

  I based this off of the last patch you took from me that fixed the
  merge conflict error, as that was the commit that had all the changes
  I needed for this set of changes."

* tag 'trace-fixes-v3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/kprobes: Support soft-mode disabling
  tracing/kprobes: Support ftrace_event_file base multibuffer
  tracing/kprobes: Pass trace_probe directly from dispatcher
  tracing/kprobes: Increment probe hit-count even if it is used by perf
  tracing/kprobes: Use bool for retprobe checker
  ftrace: Fix function probe when more than one probe is added
  ftrace: Fix the output of enabled_functions debug file
  ftrace: Fix locking in register_ftrace_function_probe()
  tracing: Add helper function trace_create_new_event() to remove duplicate code
  tracing: Modify soft-mode only if there's no other referrer
  tracing: Indicate enabled soft-mode in enable file
  tracing/kprobes: Fix to increment return event probe hit-count
  ftrace: Cleanup regex_lock and ftrace_lock around hash updating
  ftrace, kprobes: Fix a deadlock on ftrace_regex_lock
  ftrace: Have ftrace_regex_write() return either read or error
  tracing: Return error if register_ftrace_function_probe() fails for event_enable_func()
  tracing: Don't succeed if event_enable_func did not register anything
  ring-buffer: Select IRQ_WORK

tracing/kprobes: Support soft-mode disabling

2013-05-10T00:22:16+00:00

Support soft-mode disabling on kprobe-based dynamic events.
Soft-disabling is just ignoring recording if the soft disabled
flag is set.

Link: http://lkml.kernel.org/r/20130509054454.30398.7237.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Tom Zanussi 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt

tracing/kprobes: Support ftrace_event_file base multibuffer

2013-05-10T00:21:47+00:00

Support multi-buffer on kprobe-based dynamic events by
using ftrace_event_file.

Link: http://lkml.kernel.org/r/20130509054449.30398.88343.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Tom Zanussi 
Cc: Oleg Nesterov 
Cc: Srikar Dronamraju 
Signed-off-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt