Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Quentin Casasnovas]

On Mon, Dec 12, 2016 at 07:58:03AM +0100, Dmitry Vyukov wrote:
> On Sun, Dec 11, 2016 at 10:37 PM, Alexander Popov  
> wrote:
> > On 11.12.2016 12:32, Dmitry Vyukov wrote:
> >> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  
> >> wrote:
> >>> Subtract KASLR offset from the kernel addresses reported by kcov.
> >>> Tested on x86_64 and AArch64 (Hikey LeMaker).
> >>>
> >>> Signed-off-by: Alexander Popov 
> >>> ---
> >>>  kernel/kcov.c | 8 +++-
> >>>  1 file changed, 7 insertions(+), 1 deletion(-)
> >>
> >> I think generally this is the right thing to do.
> >>
> >>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
> >> "kcov: add AFL-style tracing"
> >> "kcov: size of arena is now given in bytes"
> >> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
> >> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
> >>
> >> Your patch probably conflicts with them.
> >> Should you base them on top of these patches, so that Andrew can merge
> >> it without conflicts?
> >
> > Excuse me, I can't find these patches in:
> > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
> > git://git.cmpxchg.org/linux-mmots.git
> >
> > Could you point at the tree which I can rebase onto?
> > Should I cherry-pick Quentin's patches manually?
> 
> 
> Quentin, do you know destiny of your patches? They does not seem to be
> in mm tree.

Huh since apologies, looks like I messed up my filters and completely
missed this thread.  I was going to ask where my patches landed and who
should take them...

I'm happy to re-send them rebased on the mm tree if that's where they're
going to land initially.

Thanks,
Quentin



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Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Quentin Casasnovas]

On Mon, Dec 12, 2016 at 07:58:03AM +0100, Dmitry Vyukov wrote:
> On Sun, Dec 11, 2016 at 10:37 PM, Alexander Popov  
> wrote:
> > On 11.12.2016 12:32, Dmitry Vyukov wrote:
> >> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  
> >> wrote:
> >>> Subtract KASLR offset from the kernel addresses reported by kcov.
> >>> Tested on x86_64 and AArch64 (Hikey LeMaker).
> >>>
> >>> Signed-off-by: Alexander Popov 
> >>> ---
> >>>  kernel/kcov.c | 8 +++-
> >>>  1 file changed, 7 insertions(+), 1 deletion(-)
> >>
> >> I think generally this is the right thing to do.
> >>
> >>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
> >> "kcov: add AFL-style tracing"
> >> "kcov: size of arena is now given in bytes"
> >> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
> >> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
> >>
> >> Your patch probably conflicts with them.
> >> Should you base them on top of these patches, so that Andrew can merge
> >> it without conflicts?
> >
> > Excuse me, I can't find these patches in:
> > git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
> > git://git.cmpxchg.org/linux-mmots.git
> >
> > Could you point at the tree which I can rebase onto?
> > Should I cherry-pick Quentin's patches manually?
> 
> 
> Quentin, do you know destiny of your patches? They does not seem to be
> in mm tree.

Huh since apologies, looks like I messed up my filters and completely
missed this thread.  I was going to ask where my patches landed and who
should take them...

I'm happy to re-send them rebased on the mm tree if that's where they're
going to land initially.

Thanks,
Quentin



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Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Dmitry Vyukov]

On Sun, Dec 11, 2016 at 10:37 PM, Alexander Popov  wrote:
> On 11.12.2016 12:32, Dmitry Vyukov wrote:
>> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  
>> wrote:
>>> Subtract KASLR offset from the kernel addresses reported by kcov.
>>> Tested on x86_64 and AArch64 (Hikey LeMaker).
>>>
>>> Signed-off-by: Alexander Popov 
>>> ---
>>>  kernel/kcov.c | 8 +++-
>>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> I think generally this is the right thing to do.
>>
>>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
>> "kcov: add AFL-style tracing"
>> "kcov: size of arena is now given in bytes"
>> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
>> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
>>
>> Your patch probably conflicts with them.
>> Should you base them on top of these patches, so that Andrew can merge
>> it without conflicts?
>
> Excuse me, I can't find these patches in:
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
> git://git.cmpxchg.org/linux-mmots.git
>
> Could you point at the tree which I can rebase onto?
> Should I cherry-pick Quentin's patches manually?


Quentin, do you know destiny of your patches? They does not seem to be
in mm tree.

Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Dmitry Vyukov]

On Sun, Dec 11, 2016 at 10:37 PM, Alexander Popov  wrote:
> On 11.12.2016 12:32, Dmitry Vyukov wrote:
>> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  
>> wrote:
>>> Subtract KASLR offset from the kernel addresses reported by kcov.
>>> Tested on x86_64 and AArch64 (Hikey LeMaker).
>>>
>>> Signed-off-by: Alexander Popov 
>>> ---
>>>  kernel/kcov.c | 8 +++-
>>>  1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> I think generally this is the right thing to do.
>>
>>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
>> "kcov: add AFL-style tracing"
>> "kcov: size of arena is now given in bytes"
>> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
>> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
>>
>> Your patch probably conflicts with them.
>> Should you base them on top of these patches, so that Andrew can merge
>> it without conflicts?
>
> Excuse me, I can't find these patches in:
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
> git://git.cmpxchg.org/linux-mmots.git
>
> Could you point at the tree which I can rebase onto?
> Should I cherry-pick Quentin's patches manually?


Quentin, do you know destiny of your patches? They does not seem to be
in mm tree.

Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Alexander Popov]

On 11.12.2016 12:32, Dmitry Vyukov wrote:
> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  wrote:
>> Subtract KASLR offset from the kernel addresses reported by kcov.
>> Tested on x86_64 and AArch64 (Hikey LeMaker).
>>
>> Signed-off-by: Alexander Popov 
>> ---
>>  kernel/kcov.c | 8 +++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> I think generally this is the right thing to do.
> 
>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
> "kcov: add AFL-style tracing"
> "kcov: size of arena is now given in bytes"
> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
> 
> Your patch probably conflicts with them.
> Should you base them on top of these patches, so that Andrew can merge
> it without conflicts?

Excuse me, I can't find these patches in:
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
git://git.cmpxchg.org/linux-mmots.git

Could you point at the tree which I can rebase onto?
Should I cherry-pick Quentin's patches manually?

Best regards,
Alexander

Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Alexander Popov]

On 11.12.2016 12:32, Dmitry Vyukov wrote:
> On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  wrote:
>> Subtract KASLR offset from the kernel addresses reported by kcov.
>> Tested on x86_64 and AArch64 (Hikey LeMaker).
>>
>> Signed-off-by: Alexander Popov 
>> ---
>>  kernel/kcov.c | 8 +++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> I think generally this is the right thing to do.
> 
>  There are 2 pending patches for kcov by +Quentin (hopefully in mm):
> "kcov: add AFL-style tracing"
> "kcov: size of arena is now given in bytes"
> https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
> https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ
> 
> Your patch probably conflicts with them.
> Should you base them on top of these patches, so that Andrew can merge
> it without conflicts?

Excuse me, I can't find these patches in:
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git
git://git.cmpxchg.org/linux-mmots.git

Could you point at the tree which I can rebase onto?
Should I cherry-pick Quentin's patches manually?

Best regards,
Alexander

Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Dmitry Vyukov]

On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  wrote:
> Subtract KASLR offset from the kernel addresses reported by kcov.
> Tested on x86_64 and AArch64 (Hikey LeMaker).
>
> Signed-off-by: Alexander Popov 
> ---
>  kernel/kcov.c | 8 +++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/kcov.c b/kernel/kcov.c
> index 3cbb0c8..f8f3f4c 100644
> --- a/kernel/kcov.c
> +++ b/kernel/kcov.c
> @@ -14,6 +14,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>
>  /*
>   * kcov descriptor (one per opened debugfs file).
> @@ -68,6 +69,11 @@ void notrace __sanitizer_cov_trace_pc(void)
> if (mode == KCOV_MODE_TRACE) {
> unsigned long *area;
> unsigned long pos;
> +   unsigned long ip = _RET_IP_;
> +
> +#ifdef CONFIG_RANDOMIZE_BASE
> +   ip -= kaslr_offset();
> +#endif
>
> /*
>  * There is some code that runs in interrupts but for which
> @@ -81,7 +87,7 @@ void notrace __sanitizer_cov_trace_pc(void)
> /* The first word is number of subsequent PCs. */
> pos = READ_ONCE(area[0]) + 1;
> if (likely(pos < t->kcov_size)) {
> -   area[pos] = _RET_IP_;
> +   area[pos] = ip;
> WRITE_ONCE(area[0], pos);
> }
> }
> --
> 2.7.4


Hi,

I think generally this is the right thing to do.

 There are 2 pending patches for kcov by +Quentin (hopefully in mm):
"kcov: add AFL-style tracing"
"kcov: size of arena is now given in bytes"
https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ

Your patch probably conflicts with them.
Should you base them on top of these patches, so that Andrew can merge
it without conflicts?

Re: [PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Dmitry Vyukov]

On Sun, Dec 11, 2016 at 1:50 AM, Alexander Popov  wrote:
> Subtract KASLR offset from the kernel addresses reported by kcov.
> Tested on x86_64 and AArch64 (Hikey LeMaker).
>
> Signed-off-by: Alexander Popov 
> ---
>  kernel/kcov.c | 8 +++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/kcov.c b/kernel/kcov.c
> index 3cbb0c8..f8f3f4c 100644
> --- a/kernel/kcov.c
> +++ b/kernel/kcov.c
> @@ -14,6 +14,7 @@
>  #include 
>  #include 
>  #include 
> +#include 
>
>  /*
>   * kcov descriptor (one per opened debugfs file).
> @@ -68,6 +69,11 @@ void notrace __sanitizer_cov_trace_pc(void)
> if (mode == KCOV_MODE_TRACE) {
> unsigned long *area;
> unsigned long pos;
> +   unsigned long ip = _RET_IP_;
> +
> +#ifdef CONFIG_RANDOMIZE_BASE
> +   ip -= kaslr_offset();
> +#endif
>
> /*
>  * There is some code that runs in interrupts but for which
> @@ -81,7 +87,7 @@ void notrace __sanitizer_cov_trace_pc(void)
> /* The first word is number of subsequent PCs. */
> pos = READ_ONCE(area[0]) + 1;
> if (likely(pos < t->kcov_size)) {
> -   area[pos] = _RET_IP_;
> +   area[pos] = ip;
> WRITE_ONCE(area[0], pos);
> }
> }
> --
> 2.7.4


Hi,

I think generally this is the right thing to do.

 There are 2 pending patches for kcov by +Quentin (hopefully in mm):
"kcov: add AFL-style tracing"
"kcov: size of arena is now given in bytes"
https://groups.google.com/forum/#!topic/syzkaller/gcqbIhKjGcY
https://groups.google.com/d/msg/syzkaller/gcqbIhKjGcY/KQFryjBKCAAJ

Your patch probably conflicts with them.
Should you base them on top of these patches, so that Andrew can merge
it without conflicts?

[PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Alexander Popov]

Subtract KASLR offset from the kernel addresses reported by kcov.
Tested on x86_64 and AArch64 (Hikey LeMaker).

Signed-off-by: Alexander Popov 
---
 kernel/kcov.c | 8 +++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 3cbb0c8..f8f3f4c 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -14,6 +14,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /*
  * kcov descriptor (one per opened debugfs file).
@@ -68,6 +69,11 @@ void notrace __sanitizer_cov_trace_pc(void)
if (mode == KCOV_MODE_TRACE) {
unsigned long *area;
unsigned long pos;
+   unsigned long ip = _RET_IP_;
+
+#ifdef CONFIG_RANDOMIZE_BASE
+   ip -= kaslr_offset();
+#endif
 
/*
 * There is some code that runs in interrupts but for which
@@ -81,7 +87,7 @@ void notrace __sanitizer_cov_trace_pc(void)
/* The first word is number of subsequent PCs. */
pos = READ_ONCE(area[0]) + 1;
if (likely(pos < t->kcov_size)) {
-   area[pos] = _RET_IP_;
+   area[pos] = ip;
WRITE_ONCE(area[0], pos);
}
}
-- 
2.7.4

[PATCH 2/2] kcov: make kcov work properly with KASLR enabled

[Alexander Popov]

Subtract KASLR offset from the kernel addresses reported by kcov.
Tested on x86_64 and AArch64 (Hikey LeMaker).

Signed-off-by: Alexander Popov 
---
 kernel/kcov.c | 8 +++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/kcov.c b/kernel/kcov.c
index 3cbb0c8..f8f3f4c 100644
--- a/kernel/kcov.c
+++ b/kernel/kcov.c
@@ -14,6 +14,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /*
  * kcov descriptor (one per opened debugfs file).
@@ -68,6 +69,11 @@ void notrace __sanitizer_cov_trace_pc(void)
if (mode == KCOV_MODE_TRACE) {
unsigned long *area;
unsigned long pos;
+   unsigned long ip = _RET_IP_;
+
+#ifdef CONFIG_RANDOMIZE_BASE
+   ip -= kaslr_offset();
+#endif
 
/*
 * There is some code that runs in interrupts but for which
@@ -81,7 +87,7 @@ void notrace __sanitizer_cov_trace_pc(void)
/* The first word is number of subsequent PCs. */
pos = READ_ONCE(area[0]) + 1;
if (likely(pos < t->kcov_size)) {
-   area[pos] = _RET_IP_;
+   area[pos] = ip;
WRITE_ONCE(area[0], pos);
}
}
-- 
2.7.4