2022-11-10 09:21:51

by Genjian

[permalink] [raw]
Subject: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit

From: Genjian Zhang <[email protected]>

vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
__kasan_check_write() leaves .noinstr.text section
vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
__kasan_check_write() leaves .noinstr.text section

noinstr cannot have atomic_*() functions.because they have explicit
instrumentation.Switch to arch_ prefixed atomic operation functions to
avoid the explicit instrumentation.

Reported-by: k2ci <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Genjian Zhang <[email protected]>
---
kernel/context_tracking.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 77978e372377..a09f1c19336a 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -510,7 +510,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
- atomic_set(&ct->state, state);
+ arch_atomic_set(&ct->state, state);
} else {
/*
* Even if context tracking is disabled on this CPU, because it's outside
@@ -527,7 +527,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
- atomic_set(&ct->state, state);
+ arch_atomic_set(&ct->state, state);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
@@ -535,7 +535,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
- atomic_add(state, &ct->state);
+ arch_atomic_add(state, &ct->state);
}
}
}
@@ -630,12 +630,12 @@ void noinstr __ct_user_exit(enum ctx_state state)
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
- atomic_set(&ct->state, CONTEXT_KERNEL);
+ arch_atomic_set(&ct->state, CONTEXT_KERNEL);

} else {
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
- atomic_set(&ct->state, CONTEXT_KERNEL);
+ arch_atomic_set(&ct->state, CONTEXT_KERNEL);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
@@ -643,7 +643,7 @@ void noinstr __ct_user_exit(enum ctx_state state)
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
- atomic_sub(state, &ct->state);
+ arch_atomic_sub(state, &ct->state);
}
}
}
--
2.25.1



2023-01-06 14:58:49

by Paul E. McKenney

[permalink] [raw]
Subject: Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit

On Thu, Nov 10, 2022 at 04:24:43PM +0800, Genjian wrote:
> From: Genjian Zhang <[email protected]>
>
> vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
> __kasan_check_write() leaves .noinstr.text section
> vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
> __kasan_check_write() leaves .noinstr.text section
>
> noinstr cannot have atomic_*() functions.because they have explicit
> instrumentation.Switch to arch_ prefixed atomic operation functions to
> avoid the explicit instrumentation.
>
> Reported-by: k2ci <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Genjian Zhang <[email protected]>

Apologies for the delay, but finally queued, thank you! Frederic gave
his ack off-list, which I have included in the wordsmithed version below.
Could you please check to make sure that I did not mess anything up?

Thanx, Paul

------------------------------------------------------------------------

commit 936acd859f4a7b2b0f9900e26bc972385286df6e
Author: Genjian Zhang <[email protected]>
Date: Thu Nov 10 16:24:43 2022 +0800

context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit

The following diagnostics are issued by objtool:

vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
__kasan_check_write() leaves .noinstr.text section
vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
__kasan_check_write() leaves .noinstr.text section

The reason for these diagnostics is that code marked noinstr if prohibited
from using atomic_*() functions, which have explicit instrumentation.
Therefore, switch to arch_ prefixed atomic operation functions to avoid
the explicit instrumentation.

Reported-by: k2ci <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Genjian Zhang <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index 77978e3723771..a09f1c19336ae 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -510,7 +510,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
- atomic_set(&ct->state, state);
+ arch_atomic_set(&ct->state, state);
} else {
/*
* Even if context tracking is disabled on this CPU, because it's outside
@@ -527,7 +527,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
- atomic_set(&ct->state, state);
+ arch_atomic_set(&ct->state, state);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
@@ -535,7 +535,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
- atomic_add(state, &ct->state);
+ arch_atomic_add(state, &ct->state);
}
}
}
@@ -630,12 +630,12 @@ void noinstr __ct_user_exit(enum ctx_state state)
* In this we case we don't care about any concurrency/ordering.
*/
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
- atomic_set(&ct->state, CONTEXT_KERNEL);
+ arch_atomic_set(&ct->state, CONTEXT_KERNEL);

} else {
if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
/* Tracking for vtime only, no concurrent RCU EQS accounting */
- atomic_set(&ct->state, CONTEXT_KERNEL);
+ arch_atomic_set(&ct->state, CONTEXT_KERNEL);
} else {
/*
* Tracking for vtime and RCU EQS. Make sure we don't race
@@ -643,7 +643,7 @@ void noinstr __ct_user_exit(enum ctx_state state)
* RCU only requires RCU_DYNTICKS_IDX increments to be fully
* ordered.
*/
- atomic_sub(state, &ct->state);
+ arch_atomic_sub(state, &ct->state);
}
}
}

2023-01-09 07:32:27

by Genjian

[permalink] [raw]
Subject: Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit

On Fri, Jan 6, 2023 at 10:53 PM Paul E. McKenney <[email protected]> wrote:
>
> On Thu, Nov 10, 2022 at 04:24:43PM +0800, Genjian wrote:
> > From: Genjian Zhang <[email protected]>
> >
> > vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
> > __kasan_check_write() leaves .noinstr.text section
> > vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
> > __kasan_check_write() leaves .noinstr.text section
> >
> > noinstr cannot have atomic_*() functions.because they have explicit
> > instrumentation.Switch to arch_ prefixed atomic operation functions to
> > avoid the explicit instrumentation.
> >
> > Reported-by: k2ci <[email protected]>
> > Reported-by: kernel test robot <[email protected]>
> > Signed-off-by: Genjian Zhang <[email protected]>
>
> Apologies for the delay, but finally queued, thank you! Frederic gave
> his ack off-list, which I have included in the wordsmithed version below.
> Could you please check to make sure that I did not mess anything up?
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit 936acd859f4a7b2b0f9900e26bc972385286df6e
> Author: Genjian Zhang <[email protected]>
> Date: Thu Nov 10 16:24:43 2022 +0800
>
> context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit
>
> The following diagnostics are issued by objtool:
>
> vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
> __kasan_check_write() leaves .noinstr.text section
> vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
> __kasan_check_write() leaves .noinstr.text section
>
> The reason for these diagnostics is that code marked noinstr if prohibited
> from using atomic_*() functions, which have explicit instrumentation.
> Therefore, switch to arch_ prefixed atomic operation functions to avoid
> the explicit instrumentation.
>
> Reported-by: k2ci <[email protected]>
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Genjian Zhang <[email protected]>
> Acked-by: Frederic Weisbecker <[email protected]>
> Signed-off-by: Paul E. McKenney <[email protected]>
>
> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> index 77978e3723771..a09f1c19336ae 100644
> --- a/kernel/context_tracking.c
> +++ b/kernel/context_tracking.c
> @@ -510,7 +510,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> * In this we case we don't care about any concurrency/ordering.
> */
> if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
> - atomic_set(&ct->state, state);
> + arch_atomic_set(&ct->state, state);
> } else {
> /*
> * Even if context tracking is disabled on this CPU, because it's outside
> @@ -527,7 +527,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> */
> if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
> /* Tracking for vtime only, no concurrent RCU EQS accounting */
> - atomic_set(&ct->state, state);
> + arch_atomic_set(&ct->state, state);
> } else {
> /*
> * Tracking for vtime and RCU EQS. Make sure we don't race
> @@ -535,7 +535,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> * RCU only requires RCU_DYNTICKS_IDX increments to be fully
> * ordered.
> */
> - atomic_add(state, &ct->state);
> + arch_atomic_add(state, &ct->state);
> }
> }
> }
> @@ -630,12 +630,12 @@ void noinstr __ct_user_exit(enum ctx_state state)
> * In this we case we don't care about any concurrency/ordering.
> */
> if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
> - atomic_set(&ct->state, CONTEXT_KERNEL);
> + arch_atomic_set(&ct->state, CONTEXT_KERNEL);
>
> } else {
> if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
> /* Tracking for vtime only, no concurrent RCU EQS accounting */
> - atomic_set(&ct->state, CONTEXT_KERNEL);
> + arch_atomic_set(&ct->state, CONTEXT_KERNEL);
> } else {
> /*
> * Tracking for vtime and RCU EQS. Make sure we don't race
> @@ -643,7 +643,7 @@ void noinstr __ct_user_exit(enum ctx_state state)
> * RCU only requires RCU_DYNTICKS_IDX increments to be fully
> * ordered.
> */
> - atomic_sub(state, &ct->state);
> + arch_atomic_sub(state, &ct->state);
> }
> }
> }

Seems good to me.

Thanks,

Genjian.

2023-01-09 15:33:50

by Paul E. McKenney

[permalink] [raw]
Subject: Re: [PATCH] context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit

On Mon, Jan 09, 2023 at 03:13:06PM +0800, genjian zhang wrote:
> On Fri, Jan 6, 2023 at 10:53 PM Paul E. McKenney <[email protected]> wrote:
> >
> > On Thu, Nov 10, 2022 at 04:24:43PM +0800, Genjian wrote:
> > > From: Genjian Zhang <[email protected]>
> > >
> > > vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
> > > __kasan_check_write() leaves .noinstr.text section
> > > vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
> > > __kasan_check_write() leaves .noinstr.text section
> > >
> > > noinstr cannot have atomic_*() functions.because they have explicit
> > > instrumentation.Switch to arch_ prefixed atomic operation functions to
> > > avoid the explicit instrumentation.
> > >
> > > Reported-by: k2ci <[email protected]>
> > > Reported-by: kernel test robot <[email protected]>
> > > Signed-off-by: Genjian Zhang <[email protected]>
> >
> > Apologies for the delay, but finally queued, thank you! Frederic gave
> > his ack off-list, which I have included in the wordsmithed version below.
> > Could you please check to make sure that I did not mess anything up?
> >
> > Thanx, Paul
> >
> > ------------------------------------------------------------------------
> >
> > commit 936acd859f4a7b2b0f9900e26bc972385286df6e
> > Author: Genjian Zhang <[email protected]>
> > Date: Thu Nov 10 16:24:43 2022 +0800
> >
> > context_tracking: Use arch_atomic_*() in __ct_user_enter and __ct_user_exit
> >
> > The following diagnostics are issued by objtool:
> >
> > vmlinux.o: warning: objtool: __ct_user_enter+0x45: call to
> > __kasan_check_write() leaves .noinstr.text section
> > vmlinux.o: warning: objtool: __ct_user_exit+0x3f: call to
> > __kasan_check_write() leaves .noinstr.text section
> >
> > The reason for these diagnostics is that code marked noinstr if prohibited
> > from using atomic_*() functions, which have explicit instrumentation.
> > Therefore, switch to arch_ prefixed atomic operation functions to avoid
> > the explicit instrumentation.
> >
> > Reported-by: k2ci <[email protected]>
> > Reported-by: kernel test robot <[email protected]>
> > Signed-off-by: Genjian Zhang <[email protected]>
> > Acked-by: Frederic Weisbecker <[email protected]>
> > Signed-off-by: Paul E. McKenney <[email protected]>
> >
> > diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
> > index 77978e3723771..a09f1c19336ae 100644
> > --- a/kernel/context_tracking.c
> > +++ b/kernel/context_tracking.c
> > @@ -510,7 +510,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> > * In this we case we don't care about any concurrency/ordering.
> > */
> > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
> > - atomic_set(&ct->state, state);
> > + arch_atomic_set(&ct->state, state);
> > } else {
> > /*
> > * Even if context tracking is disabled on this CPU, because it's outside
> > @@ -527,7 +527,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> > */
> > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
> > /* Tracking for vtime only, no concurrent RCU EQS accounting */
> > - atomic_set(&ct->state, state);
> > + arch_atomic_set(&ct->state, state);
> > } else {
> > /*
> > * Tracking for vtime and RCU EQS. Make sure we don't race
> > @@ -535,7 +535,7 @@ void noinstr __ct_user_enter(enum ctx_state state)
> > * RCU only requires RCU_DYNTICKS_IDX increments to be fully
> > * ordered.
> > */
> > - atomic_add(state, &ct->state);
> > + arch_atomic_add(state, &ct->state);
> > }
> > }
> > }
> > @@ -630,12 +630,12 @@ void noinstr __ct_user_exit(enum ctx_state state)
> > * In this we case we don't care about any concurrency/ordering.
> > */
> > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE))
> > - atomic_set(&ct->state, CONTEXT_KERNEL);
> > + arch_atomic_set(&ct->state, CONTEXT_KERNEL);
> >
> > } else {
> > if (!IS_ENABLED(CONFIG_CONTEXT_TRACKING_IDLE)) {
> > /* Tracking for vtime only, no concurrent RCU EQS accounting */
> > - atomic_set(&ct->state, CONTEXT_KERNEL);
> > + arch_atomic_set(&ct->state, CONTEXT_KERNEL);
> > } else {
> > /*
> > * Tracking for vtime and RCU EQS. Make sure we don't race
> > @@ -643,7 +643,7 @@ void noinstr __ct_user_exit(enum ctx_state state)
> > * RCU only requires RCU_DYNTICKS_IDX increments to be fully
> > * ordered.
> > */
> > - atomic_sub(state, &ct->state);
> > + arch_atomic_sub(state, &ct->state);
> > }
> > }
> > }
>
> Seems good to me.

Thank you for checking!

Thanx, Paul