linux-toradex.git/kernel/kprobes.c, branch v2.6.34

kprobes: Calculate the index correctly when freeing the out-of-line execution slot

2010-03-11T13:06:16+00:00

From : Ananth N Mavinakayanahalli 

When freeing the instruction slot, the arithmetic to calculate
the index of the slot in the page needs to account for the total
size of the instruction on the various architectures.

Calculate the index correctly when freeing the out-of-line
execution slot.

Reported-by: Sachin Sant 
Reported-by: Heiko Carstens 
Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Masami Hiramatsu 
LKML-Reference: <4B9667AB.9050507@redhat.com>
Signed-off-by: Ingo Molnar

kprobes: Jump optimization sysctl interface

2010-02-25T16:49:25+00:00

Add /proc/sys/debug/kprobes-optimization sysctl which enables
and disables kprobes jump optimization on the fly for debugging.

Changes in v7:
 - Remove ctl_name = CTL_UNNUMBERED for upstream compatibility.

Changes in v6:
- Update comments and coding style.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Srikar Dronamraju 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
Cc: Anders Kaseorg 
Cc: Tim Abbott 
Cc: Andi Kleen 
Cc: Jason Baron 
Cc: Mathieu Desnoyers 
Cc: Frederic Weisbecker 
Cc: Ananth N Mavinakayanahalli 
LKML-Reference: <20100225133415.6725.8274.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar

kprobes: Introduce kprobes jump optimization

2010-02-25T16:49:24+00:00

Introduce kprobes jump optimization arch-independent parts.
Kprobes uses breakpoint instruction for interrupting execution
flow, on some architectures, it can be replaced by a jump
instruction and interruption emulation code. This gains kprobs'
performance drastically.

To enable this feature, set CONFIG_OPTPROBES=y (default y if the
arch supports OPTPROBE).

Changes in v9:
 - Fix a bug to optimize probe when enabling.
 - Check nearby probes can be optimize/unoptimize when disarming/arming
   kprobes, instead of registering/unregistering. This will help
   kprobe-tracer because most of probes on it are usually disabled.

Changes in v6:
 - Cleanup coding style for readability.
 - Add comments around get/put_online_cpus().

Changes in v5:
 - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex
   deadlock.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Srikar Dronamraju 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
Cc: Anders Kaseorg 
Cc: Tim Abbott 
Cc: Andi Kleen 
Cc: Jason Baron 
Cc: Mathieu Desnoyers 
Cc: Frederic Weisbecker 
Cc: Ananth N Mavinakayanahalli 
LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar

kprobes: Introduce generic insn_slot framework

2010-02-25T16:49:24+00:00

Make insn_slot framework support various size slots.
Current insn_slot just supports one-size instruction buffer
slot. However, kprobes jump optimization needs larger size
buffers.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Srikar Dronamraju 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
Cc: Anders Kaseorg 
Cc: Tim Abbott 
Cc: Andi Kleen 
Cc: Jason Baron 
Cc: Mathieu Desnoyers 
Cc: Frederic Weisbecker 
Cc: Ananth N Mavinakayanahalli 
LKML-Reference: <20100225133358.6725.82430.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Srikar Dronamraju 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Frederic Weisbecker 
Cc: H. Peter Anvin 
Cc: Anders Kaseorg 
Cc: Tim Abbott 
Cc: Andi Kleen 
Cc: Jason Baron 
Cc: Mathieu Desnoyers

kprobes: Add mcount to the kprobes blacklist

2010-02-05T07:13:57+00:00

Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Ananth N Mavinakayanahalli 
Cc: Steven Rostedt 
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar

kprobes: Check probe address is reserved

2010-02-04T08:36:19+00:00

Check whether the address of new probe is already reserved by
ftrace or alternatives (on x86) when registering new probe.
If reserved, it returns an error and not register the probe.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Steven Rostedt 
Cc: przemyslaw@pawelczyk.it
Cc: Frederic Weisbecker 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Mathieu Desnoyers 
Cc: Jason Baron 
LKML-Reference: <20100202214918.4694.94179.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar

kprobes: Disable booster when CONFIG_PREEMPT=y

2010-02-04T08:36:18+00:00

Disable kprobe booster when CONFIG_PREEMPT=y at this time,
because it can't ensure that all kernel threads preempted on
kprobe's boosted slot run out from the slot even using
freeze_processes().

The booster on preemptive kernel will be resumed if
synchronize_tasks() or something like that is introduced.

Signed-off-by: Masami Hiramatsu 
Cc: systemtap 
Cc: DLE 
Cc: Ananth N Mavinakayanahalli 
Cc: Frederic Weisbecker 
Cc: Jim Keniston 
Cc: Mathieu Desnoyers 
Cc: Steven Rostedt 
LKML-Reference: <20100202214904.4694.24330.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar

kprobes: Fix distinct type warning

2009-12-28T09:25:31+00:00

Every time I see this:

 kernel/kprobes.c: In function 'register_kretprobe':
 kernel/kprobes.c:1038: warning: comparison of distinct pointer types lacks a cast

I'm wondering if something changed in common code and we need to
do something for s390. Apparently that's not the case.
Let's get rid of this annoying warning.

Signed-off-by: Heiko Carstens 
Acked-by: Ananth N Mavinakayanahalli 
Cc: Masami Hiramatsu 
LKML-Reference: <20091221120224.GA4471@osiris.boeblingen.de.ibm.com>
Signed-off-by: Ingo Molnar

Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-12-05T23:30:21+00:00

* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (470 commits)
  x86: Fix comments of register/stack access functions
  perf tools: Replace %m with %a in sscanf
  hw-breakpoints: Keep track of user disabled breakpoints
  tracing/syscalls: Make syscall events print callbacks static
  tracing: Add DEFINE_EVENT(), DEFINE_SINGLE_EVENT() support to docbook
  perf: Don't free perf_mmap_data until work has been done
  perf_event: Fix compile error
  perf tools: Fix _GNU_SOURCE macro related strndup() build error
  trace_syscalls: Remove unused syscall_name_to_nr()
  trace_syscalls: Simplify syscall profile
  trace_syscalls: Remove duplicate init_enter_##sname()
  trace_syscalls: Add syscall_nr field to struct syscall_metadata
  trace_syscalls: Remove enter_id exit_id
  trace_syscalls: Set event_enter_##sname->data to its metadata
  trace_syscalls: Remove unused event_syscall_enter and event_syscall_exit
  perf_event: Initialize data.period in perf_swevent_hrtimer()
  perf probe: Simplify event naming
  perf probe: Add --list option for listing current probe events
  perf probe: Add argv_split() from lib/argv_split.c
  perf probe: Move probe event utility functions to probe-event.c
  ...

kprobes: Sanitize struct kretprobe_instance allocations

2009-11-02T16:00:18+00:00

For as long as kretprobes have existed, we've allocated NR_CPUS
instances of kretprobe_instance structures. With the default
value of CONFIG_NR_CPUS increasing on certain architectures, we
are potentially wasting kernel memory.

See http://sourceware.org/bugzilla/show_bug.cgi?id=10839#c3 for
more details.

Use a saner num_possible_cpus() instead of NR_CPUS for
allocation.

Signed-off-by: Ananth N Mavinakayanahalli 
Acked-by: Masami Hiramatsu 
Cc: Jim Keniston 
Cc: fweisbec@gmail.com
LKML-Reference: <20091030135310.GA22230@in.ibm.com>
Signed-off-by: Ingo Molnar