Re: [PATCH 0/4] powerpc: build out kprobes blacklist

[Naveen N. Rao]

On 2017/04/27 11:24AM, Masami Hiramatsu wrote:
> Hello Naveen,
> 
> On Tue, 25 Apr 2017 22:04:05 +0530
> "Naveen N. Rao"  wrote:
> 
> > This is the second in the series of patches to build out an appropriate
> > kprobes blacklist. This series blacklists system_call() and functions
> > involved when handling the trap itself. Not everything is covered, but
> > this is the first set of functions that I have tested with. More
> > patches to follow once I expand my tests.
> 
> OK, btw, have you tested to put kprobes on these functions and
> saw kernel panic happened?

Thanks for the question! I re-checked and I just realized I hadn't 
tested the PAPR case (stolen time accounting). On testing, I just found 
that those functions are not a problem since they are only invoked when 
we are coming in from user-space and not when we take a trap in-kernel.  
I will re-spin patch 3/4. Other functions have been tested to cause 
issues with kprobes.

There are still a few more functions involved (especially with 
CONFIG_PREEMPT) where I couldn't reproduce an issue, so I haven't 
included those in this series.  I am continuing to test this further and 
will post subsequent patches once I work out which other functions are 
problematic.

> 
> > I have converted many labels into private -- these are labels that I
> > felt are not necessary to read stack traces. If any of those are
> > important to have, please let me know.
> 
> At least from the viewpoint of kprobe-blacklist macros, it seems
> good to me :)
> 
> Reviewed-by: Masami Hiramatsu 
> 
> for this series.
> 
> Thank you,

Thanks for the review!
- Naveen

Re: [PATCH 0/4] powerpc: build out kprobes blacklist

[Masami Hiramatsu]

Hello Naveen,

On Tue, 25 Apr 2017 22:04:05 +0530
"Naveen N. Rao"  wrote:

> This is the second in the series of patches to build out an appropriate
> kprobes blacklist. This series blacklists system_call() and functions
> involved when handling the trap itself. Not everything is covered, but
> this is the first set of functions that I have tested with. More
> patches to follow once I expand my tests.

OK, btw, have you tested to put kprobes on these functions and
saw kernel panic happened?

> I have converted many labels into private -- these are labels that I
> felt are not necessary to read stack traces. If any of those are
> important to have, please let me know.

At least from the viewpoint of kprobe-blacklist macros, it seems
good to me :)

Reviewed-by: Masami Hiramatsu 

for this series.

Thank you,

> 
> - Naveen
> 
> Naveen N. Rao (4):
>   powerpc/kprobes: cleanup system_call_common and blacklist it from
> kprobes
>   powerpc/kprobes: un-blacklist system_call() from kprobes
>   powerpc/kprobes: blacklist functions invoked on a trap
>   powerpc/kprobes: blacklist functions involved when returning from
> exception
> 
>  arch/powerpc/kernel/entry_64.S   | 94 
> +++-
>  arch/powerpc/kernel/exceptions-64s.S |  1 +
>  arch/powerpc/kernel/time.c   |  3 ++
>  arch/powerpc/kernel/traps.c  |  3 ++
>  arch/powerpc/platforms/pseries/dtl.c |  2 +
>  5 files changed, 60 insertions(+), 43 deletions(-)
> 
> -- 
> 2.12.1
> 


-- 
Masami Hiramatsu 

[PATCH 0/4] powerpc: build out kprobes blacklist

[Naveen N. Rao]

This is the second in the series of patches to build out an appropriate
kprobes blacklist. This series blacklists system_call() and functions
involved when handling the trap itself. Not everything is covered, but
this is the first set of functions that I have tested with. More
patches to follow once I expand my tests.

I have converted many labels into private -- these are labels that I
felt are not necessary to read stack traces. If any of those are
important to have, please let me know.

- Naveen

Naveen N. Rao (4):
  powerpc/kprobes: cleanup system_call_common and blacklist it from
kprobes
  powerpc/kprobes: un-blacklist system_call() from kprobes
  powerpc/kprobes: blacklist functions invoked on a trap
  powerpc/kprobes: blacklist functions involved when returning from
exception

 arch/powerpc/kernel/entry_64.S   | 94 +++-
 arch/powerpc/kernel/exceptions-64s.S |  1 +
 arch/powerpc/kernel/time.c   |  3 ++
 arch/powerpc/kernel/traps.c  |  3 ++
 arch/powerpc/platforms/pseries/dtl.c |  2 +
 5 files changed, 60 insertions(+), 43 deletions(-)

-- 
2.12.1