subject:"Re\: \[PATCH\] kprobes\: bugfix\: makes kprobes\/enabled works correctly for optimized kprobes."

Re: [PATCH] kprobes: bugfix: makes kprobes/enabled works correctly for optimized kprobes.

2015-01-19 Thread Masami Hiramatsu

(2015/01/20 11:51), Wang Nan wrote:
> debugfs/kprobes/enabled doesn't work correctly on optimized kprobes.
> Masami Hiramatsu has a test report on x86_64 platform:
> 
> https://lkml.org/lkml/2015/1/19/274
> 
> This patch forces it to unoptimize kprobe if kprobes_all_disarmed
> is set. It also checks the flag in unregistering path for skipping
> unneeded disarming process when kprobes globally disarmed.
> 

OK, here is the test result.

[root@localhost tracing]# echo p do_fork+5 > kprobe_events
[root@localhost tracing]# echo $$ > set_ftrace_pid
[root@localhost tracing]# echo 1 > events/kprobes/p_do_fork_5/enable
[root@localhost tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 1/1   #P:8
#
#  _-=> irqs-off
# / _=> need-resched
#| / _---=> hardirq/softirq
#|| / _--=> preempt-depth
#||| / delay
#   TASK-PID   CPU#  TIMESTAMP  FUNCTION
#  | |   |      | |
bash-11466 [004] d...  4548.420463: p_do_fork_5: (do_fork+0x5/0x360)
[root@localhost tracing]# cat ../kprobes/list
810bc1c5  k  do_fork+0x5[OPTIMIZED]
[root@localhost tracing]# echo 0 > ../kprobes/enabled   # kprobes globally 
disabled
[root@localhost tracing]# echo > trace  # clear trace buffer
[root@localhost tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 0/0   #P:8
#
#  _-=> irqs-off
# / _=> need-resched
#| / _---=> hardirq/softirq
#|| / _--=> preempt-depth
#||| / delay
#   TASK-PID   CPU#  TIMESTAMP  FUNCTION
#  | |   |      | |  # No event traced!
[root@localhost tracing]# echo 0 > events/kprobes/p_do_fork_5/enable
[root@localhost tracing]# echo > kprobe_events
[root@localhost tracing]# cat ../kprobes/list
[root@localhost tracing]#   # And we can safely 
remove the probe
-

Now it looks good to me :)

Acked-by: Masami Hiramatsu 
Tested-by: Masami Hiramatsu 

Ingo,
Could you pull this patch to your -tip tree?

Thank you,

> Signed-off-by: Wang Nan 
> ---
>  kernel/kprobes.c | 11 +--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 9471710..fb995ef 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -869,7 +869,8 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
>  {
>   struct kprobe *_p;
>  
> - unoptimize_kprobe(p, false);/* Try to unoptimize */
> + /* Try to unoptimize */
> + unoptimize_kprobe(p, kprobes_all_disarmed);
>  
>   if (!kprobe_queued(p)) {
>   arch_disarm_kprobe(p);
> @@ -1571,7 +1572,13 @@ static struct kprobe *__disable_kprobe(struct kprobe 
> *p)
>  
>   /* Try to disarm and disable this/parent probe */
>   if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
> - disarm_kprobe(orig_p, true);
> + /*
> +  * If kprobes_all_disarmed is set, orig_p
> +  * should have already been disarmed, so
> +  * skip unneed disarming process.
> +  */
> + if (!kprobes_all_disarmed)
> + disarm_kprobe(orig_p, true);
>   orig_p->flags |= KPROBE_FLAG_DISABLED;
>   }
>   }
> 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com


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Re: [PATCH] kprobes: bugfix: makes kprobes/enabled works correctly for optimized kprobes.

2015-01-19 Thread Masami Hiramatsu

(2015/01/20 11:51), Wang Nan wrote:
 debugfs/kprobes/enabled doesn't work correctly on optimized kprobes.
 Masami Hiramatsu has a test report on x86_64 platform:
 
 https://lkml.org/lkml/2015/1/19/274
 
 This patch forces it to unoptimize kprobe if kprobes_all_disarmed
 is set. It also checks the flag in unregistering path for skipping
 unneeded disarming process when kprobes globally disarmed.
 

OK, here is the test result.

[root@localhost tracing]# echo p do_fork+5  kprobe_events
[root@localhost tracing]# echo $$  set_ftrace_pid
[root@localhost tracing]# echo 1  events/kprobes/p_do_fork_5/enable
[root@localhost tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 1/1   #P:8
#
#  _-= irqs-off
# / _= need-resched
#| / _---= hardirq/softirq
#|| / _--= preempt-depth
#||| / delay
#   TASK-PID   CPU#  TIMESTAMP  FUNCTION
#  | |   |      | |
bash-11466 [004] d...  4548.420463: p_do_fork_5: (do_fork+0x5/0x360)
[root@localhost tracing]# cat ../kprobes/list
810bc1c5  k  do_fork+0x5[OPTIMIZED]
[root@localhost tracing]# echo 0  ../kprobes/enabled   # kprobes globally 
disabled
[root@localhost tracing]# echo  trace  # clear trace buffer
[root@localhost tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 0/0   #P:8
#
#  _-= irqs-off
# / _= need-resched
#| / _---= hardirq/softirq
#|| / _--= preempt-depth
#||| / delay
#   TASK-PID   CPU#  TIMESTAMP  FUNCTION
#  | |   |      | |  # No event traced!
[root@localhost tracing]# echo 0  events/kprobes/p_do_fork_5/enable
[root@localhost tracing]# echo  kprobe_events
[root@localhost tracing]# cat ../kprobes/list
[root@localhost tracing]#   # And we can safely 
remove the probe
-

Now it looks good to me :)

Acked-by: Masami Hiramatsu masami.hiramatsu...@hitachi.com
Tested-by: Masami Hiramatsu masami.hiramatsu...@hitachi.com

Ingo,
Could you pull this patch to your -tip tree?

Thank you,

 Signed-off-by: Wang Nan wangn...@huawei.com
 ---
  kernel/kprobes.c | 11 +--
  1 file changed, 9 insertions(+), 2 deletions(-)
 
 diff --git a/kernel/kprobes.c b/kernel/kprobes.c
 index 9471710..fb995ef 100644
 --- a/kernel/kprobes.c
 +++ b/kernel/kprobes.c
 @@ -869,7 +869,8 @@ static void __disarm_kprobe(struct kprobe *p, bool reopt)
  {
   struct kprobe *_p;
  
 - unoptimize_kprobe(p, false);/* Try to unoptimize */
 + /* Try to unoptimize */
 + unoptimize_kprobe(p, kprobes_all_disarmed);
  
   if (!kprobe_queued(p)) {
   arch_disarm_kprobe(p);
 @@ -1571,7 +1572,13 @@ static struct kprobe *__disable_kprobe(struct kprobe 
 *p)
  
   /* Try to disarm and disable this/parent probe */
   if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
 - disarm_kprobe(orig_p, true);
 + /*
 +  * If kprobes_all_disarmed is set, orig_p
 +  * should have already been disarmed, so
 +  * skip unneed disarming process.
 +  */
 + if (!kprobes_all_disarmed)
 + disarm_kprobe(orig_p, true);
   orig_p-flags |= KPROBE_FLAG_DISABLED;
   }
   }
 


-- 
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com


--
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Re: [PATCH] kprobes: bugfix: makes kprobes/enabled works correctly for optimized kprobes.

Re: [PATCH] kprobes: bugfix: makes kprobes/enabled works correctly for optimized kprobes.

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