> On Aug 26, 2019, at 8:08 AM, Song Liu wrote:
>
>
>
>> On Aug 26, 2019, at 2:23 AM, Peter Zijlstra wrote:
>>
>> So only the high mapping is ever executable; the identity map should not
>> be. Both should be RO.
>>
>>> kprobe (with CONFIG_KPROBES_ON_FTRACE) should work on kernel identity
> On Aug 26, 2019, at 8:56 AM, Steven Rostedt wrote:
>
> On Mon, 26 Aug 2019 15:41:24 +
> Nadav Amit wrote:
>
>>> Anyway, I believe Nadav has some patches that converts ftrace to use
>>> the shadow page modification trick somewhere.
>>
>> For the record - here is my previous patch:
>> ht
On Mon, Aug 26, 2019 at 03:41:24PM +, Nadav Amit wrote:
> For the record - here is my previous patch:
> https://lkml.org/lkml/2018/12/5/211
Thanks!
On Mon, 26 Aug 2019 15:41:24 +
Nadav Amit wrote:
> > Anyway, I believe Nadav has some patches that converts ftrace to use
> > the shadow page modification trick somewhere.
>
> For the record - here is my previous patch:
> https://lkml.org/lkml/2018/12/5/211
FYI, when referencing older pat
> On Aug 26, 2019, at 4:33 AM, Steven Rostedt wrote:
>
> On Fri, 23 Aug 2019 11:36:37 +0200
> Peter Zijlstra wrote:
>
>> On Thu, Aug 22, 2019 at 10:23:35PM -0700, Song Liu wrote:
>>> As 4k pages check was removed from cpa [1], set_kernel_text_rw() leads to
>>> split_large_page() for all kernel
> On Aug 26, 2019, at 2:23 AM, Peter Zijlstra wrote:
>
> So only the high mapping is ever executable; the identity map should not
> be. Both should be RO.
>
>> kprobe (with CONFIG_KPROBES_ON_FTRACE) should work on kernel identity
>> mapping.
>
> Please provide more information; kprobes shou
On Mon, Aug 26, 2019 at 07:33:08AM -0400, Steven Rostedt wrote:
> Anyway, I believe Nadav has some patches that converts ftrace to use
> the shadow page modification trick somewhere.
>
> Or we also need the text_poke batch processing (did that get upstream?).
It did. And I just did that patch; I'
On Fri, 23 Aug 2019 11:36:37 +0200
Peter Zijlstra wrote:
> On Thu, Aug 22, 2019 at 10:23:35PM -0700, Song Liu wrote:
> > As 4k pages check was removed from cpa [1], set_kernel_text_rw() leads to
> > split_large_page() for all kernel text pages. This means a single kprobe
> > will put all kernel t
On Mon, Aug 26, 2019 at 04:40:23AM +, Song Liu wrote:
> Cc: Steven Rostedt and Suresh Siddha
>
> Hi Peter,
>
> > On Aug 23, 2019, at 2:36 AM, Peter Zijlstra wrote:
> >
> > On Thu, Aug 22, 2019 at 10:23:35PM -0700, Song Liu wrote:
> >> As 4k pages check was removed from cpa [1], set_kernel_
Cc: Steven Rostedt and Suresh Siddha
Hi Peter,
> On Aug 23, 2019, at 2:36 AM, Peter Zijlstra wrote:
>
> On Thu, Aug 22, 2019 at 10:23:35PM -0700, Song Liu wrote:
>> As 4k pages check was removed from cpa [1], set_kernel_text_rw() leads to
>> split_large_page() for all kernel text pages. This m
On Thu, Aug 22, 2019 at 10:23:35PM -0700, Song Liu wrote:
> As 4k pages check was removed from cpa [1], set_kernel_text_rw() leads to
> split_large_page() for all kernel text pages. This means a single kprobe
> will put all kernel text in 4k pages:
>
> root@ ~# grep 8100- /sys/kernel/deb
As 4k pages check was removed from cpa [1], set_kernel_text_rw() leads to
split_large_page() for all kernel text pages. This means a single kprobe
will put all kernel text in 4k pages:
root@ ~# grep 8100- /sys/kernel/debug/page_tables/kernel
0x8100-0x8240 20
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