* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
[not found] ` <20210715035149.GI4397@paulmck-ThinkPad-P17-Gen-1>
@ 2021-07-15 8:45 ` Zhouyi Zhou
2021-07-15 18:09 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Zhouyi Zhou @ 2021-07-15 8:45 UTC (permalink / raw)
To: paulmck
Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan,
Joel Fernandes, Google, rcu, linux-kernel, apw, joe, ast, daniel,
andrii, kafai, songliubraving, yhs, john.fastabend, kpsingh, bpf
On Thu, Jul 15, 2021 at 11:51 AM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Wed, Jul 14, 2021 at 12:44:36PM +0800, Zhouyi Zhou wrote:
> > On Tue, Jul 13, 2021 at 11:19 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > >
> > > On Tue, Jul 13, 2021 at 06:18:12AM -0700, Paul E. McKenney wrote:
> > > > On Tue, Jul 13, 2021 at 09:09:04AM -0400, Mathieu Desnoyers wrote:
> > > > > ----- On Jul 13, 2021, at 12:16 AM, paulmck paulmck@kernel.org wrote:
> > > > >
> > > > > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote:
> > > > > >> From: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > >>
> > > > > >> Hi Paul,
> > > > > >>
> > > > > >> During my studying of RCU, I did a grep in the kernel source tree.
> > > > > >> I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE
> > > > > >> should be CONFIG_TASKS_TRACE_RCU instead.
> > > > > >>
> > > > > >> Without memory fencing, the idle/userspace task inspection may not
> > > > > >> be so accurate.
> > > > > >>
> > > > > >> Thanks for your constant encouragement for my studying.
> > > > > >>
> > > > > >> Best Wishes
> > > > > >> Zhouyi
> > > > > >>
> > > > > >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > >
> > > > > > Good eyes, and those could cause real bugs, so thank you!
> > > > >
> > > > > Hi Paul,
> > > > >
> > > > > This makes me wonder: what is missing testing-wise in rcutorture to
> > > > > catch those issues with testing before they reach mainline ?
> > > >
> > > > My guess: Running on weakly ordered architectures. ;-)
> > >
> > > And another guess: A tool that identifies use of Kconfig options
> > > that are not defined in any Kconfig* file.
> > Based on Paul's second guess ;-), I did a small research, and I think
> > the best answer is to modify scripts/checkpatch.pl. We modify checkpatch.pl
> > to identify use of Kconfig options that are not defined in any Kconfig* file.
> >
> > As I am a C/C++ programmer, I would be glad to take some time to learn
> > perl (checkpatch is implented in perl) first if no other volunteer is
> > about to do it ;-)
>
> I haven't heard anyone else volunteer. ;-)
>
> Others might have opinions on where best to implement these checks,
> but I must confess that I have not given it much thought.
I recklessly cc the maintainers of checkpatch.pl without your
permission to see others' opion,
and I begin to study perl at the same time, after all, learning
something is always good ;-)
>
> Thanx, Paul
Best Wishes
Zhouyi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
2021-07-15 8:45 ` [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE Zhouyi Zhou
@ 2021-07-15 18:09 ` Paul E. McKenney
2021-07-17 22:03 ` Zhouyi Zhou
0 siblings, 1 reply; 6+ messages in thread
From: Paul E. McKenney @ 2021-07-15 18:09 UTC (permalink / raw)
To: Zhouyi Zhou
Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan,
Joel Fernandes, Google, rcu, linux-kernel, apw, joe, ast, daniel,
andrii, kafai, songliubraving, yhs, john.fastabend, kpsingh, bpf
On Thu, Jul 15, 2021 at 04:45:04PM +0800, Zhouyi Zhou wrote:
> On Thu, Jul 15, 2021 at 11:51 AM Paul E. McKenney <paulmck@kernel.org> wrote:
> >
> > On Wed, Jul 14, 2021 at 12:44:36PM +0800, Zhouyi Zhou wrote:
> > > On Tue, Jul 13, 2021 at 11:19 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > >
> > > > On Tue, Jul 13, 2021 at 06:18:12AM -0700, Paul E. McKenney wrote:
> > > > > On Tue, Jul 13, 2021 at 09:09:04AM -0400, Mathieu Desnoyers wrote:
> > > > > > ----- On Jul 13, 2021, at 12:16 AM, paulmck paulmck@kernel.org wrote:
> > > > > >
> > > > > > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote:
> > > > > > >> From: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > >>
> > > > > > >> Hi Paul,
> > > > > > >>
> > > > > > >> During my studying of RCU, I did a grep in the kernel source tree.
> > > > > > >> I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE
> > > > > > >> should be CONFIG_TASKS_TRACE_RCU instead.
> > > > > > >>
> > > > > > >> Without memory fencing, the idle/userspace task inspection may not
> > > > > > >> be so accurate.
> > > > > > >>
> > > > > > >> Thanks for your constant encouragement for my studying.
> > > > > > >>
> > > > > > >> Best Wishes
> > > > > > >> Zhouyi
> > > > > > >>
> > > > > > >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > >
> > > > > > > Good eyes, and those could cause real bugs, so thank you!
> > > > > >
> > > > > > Hi Paul,
> > > > > >
> > > > > > This makes me wonder: what is missing testing-wise in rcutorture to
> > > > > > catch those issues with testing before they reach mainline ?
> > > > >
> > > > > My guess: Running on weakly ordered architectures. ;-)
> > > >
> > > > And another guess: A tool that identifies use of Kconfig options
> > > > that are not defined in any Kconfig* file.
> > > Based on Paul's second guess ;-), I did a small research, and I think
> > > the best answer is to modify scripts/checkpatch.pl. We modify checkpatch.pl
> > > to identify use of Kconfig options that are not defined in any Kconfig* file.
> > >
> > > As I am a C/C++ programmer, I would be glad to take some time to learn
> > > perl (checkpatch is implented in perl) first if no other volunteer is
> > > about to do it ;-)
> >
> > I haven't heard anyone else volunteer. ;-)
> >
> > Others might have opinions on where best to implement these checks,
> > but I must confess that I have not given it much thought.
> I recklessly cc the maintainers of checkpatch.pl without your
> permission to see others' opion,
> and I begin to study perl at the same time, after all, learning
> something is always good ;-)
Works for me!
Thanx, Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
2021-07-15 18:09 ` Paul E. McKenney
@ 2021-07-17 22:03 ` Zhouyi Zhou
2021-07-18 21:08 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Zhouyi Zhou @ 2021-07-17 22:03 UTC (permalink / raw)
To: paulmck
Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan,
Joel Fernandes, Google, rcu, linux-kernel, apw, joe, ast, daniel,
andrii, kafai, songliubraving, yhs, john.fastabend, kpsingh, bpf,
mingo
Hi Paul
During the research, I found a already existing tool to detect
undefined Kconfig macro:
scripts/checkkconfigsymbols.py. It is marvellous!
By invoking ./scripts/checkkconfigsymbols.py > /tmp/log, I found
following possibly undefined Kconfig macros
which may need our attention:
PREEMPT_LOCK
Referencing files: include/linux/lockdep_types.h
PREEMT_DYNAMIC
Referencing files: kernel/entry/common.c
TREE_PREEMPT_RCU
Referencing files: arch/sh/configs/sdk7786_defconfig
RCU_CPU_STALL_INFO
Referencing files: arch/xtensa/configs/nommu_kc705_defconfig
RCU_NOCB_CPU_ALL
Referencing files:
Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst
RCU_TORTURE_TESTS
Referencing files: kernel/rcu/rcutorture.c
and finally the macro which drive me to do this research
TASKS_RCU_TRACE
Referencing files: include/linux/rcupdate.h, kernel/rcu/tree_plugin.h
On Fri, Jul 16, 2021 at 2:09 AM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> On Thu, Jul 15, 2021 at 04:45:04PM +0800, Zhouyi Zhou wrote:
> > On Thu, Jul 15, 2021 at 11:51 AM Paul E. McKenney <paulmck@kernel.org> wrote:
> > >
> > > On Wed, Jul 14, 2021 at 12:44:36PM +0800, Zhouyi Zhou wrote:
> > > > On Tue, Jul 13, 2021 at 11:19 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > > >
> > > > > On Tue, Jul 13, 2021 at 06:18:12AM -0700, Paul E. McKenney wrote:
> > > > > > On Tue, Jul 13, 2021 at 09:09:04AM -0400, Mathieu Desnoyers wrote:
> > > > > > > ----- On Jul 13, 2021, at 12:16 AM, paulmck paulmck@kernel.org wrote:
> > > > > > >
> > > > > > > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote:
> > > > > > > >> From: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > > >>
> > > > > > > >> Hi Paul,
> > > > > > > >>
> > > > > > > >> During my studying of RCU, I did a grep in the kernel source tree.
> > > > > > > >> I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE
> > > > > > > >> should be CONFIG_TASKS_TRACE_RCU instead.
> > > > > > > >>
> > > > > > > >> Without memory fencing, the idle/userspace task inspection may not
> > > > > > > >> be so accurate.
> > > > > > > >>
> > > > > > > >> Thanks for your constant encouragement for my studying.
> > > > > > > >>
> > > > > > > >> Best Wishes
> > > > > > > >> Zhouyi
> > > > > > > >>
> > > > > > > >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > > >
> > > > > > > > Good eyes, and those could cause real bugs, so thank you!
> > > > > > >
> > > > > > > Hi Paul,
> > > > > > >
> > > > > > > This makes me wonder: what is missing testing-wise in rcutorture to
> > > > > > > catch those issues with testing before they reach mainline ?
> > > > > >
> > > > > > My guess: Running on weakly ordered architectures. ;-)
> > > > >
> > > > > And another guess: A tool that identifies use of Kconfig options
> > > > > that are not defined in any Kconfig* file.
> > > > Based on Paul's second guess ;-), I did a small research, and I think
> > > > the best answer is to modify scripts/checkpatch.pl. We modify checkpatch.pl
> > > > to identify use of Kconfig options that are not defined in any Kconfig* file.
> > > >
> > > > As I am a C/C++ programmer, I would be glad to take some time to learn
> > > > perl (checkpatch is implented in perl) first if no other volunteer is
> > > > about to do it ;-)
> > >
> > > I haven't heard anyone else volunteer. ;-)
> > >
> > > Others might have opinions on where best to implement these checks,
> > > but I must confess that I have not given it much thought.
> > I recklessly cc the maintainers of checkpatch.pl without your
> > permission to see others' opion,
> > and I begin to study perl at the same time, after all, learning
> > something is always good ;-)
>
> Works for me!
>
> Thanx, Paul
Best Wishes
Zhouyi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
2021-07-17 22:03 ` Zhouyi Zhou
@ 2021-07-18 21:08 ` Paul E. McKenney
2021-07-20 1:39 ` Randy Dunlap
0 siblings, 1 reply; 6+ messages in thread
From: Paul E. McKenney @ 2021-07-18 21:08 UTC (permalink / raw)
To: Zhouyi Zhou
Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan,
Joel Fernandes, Google, rcu, linux-kernel, apw, joe, ast, daniel,
andrii, kafai, songliubraving, yhs, john.fastabend, kpsingh, bpf,
mingo
On Sun, Jul 18, 2021 at 06:03:34AM +0800, Zhouyi Zhou wrote:
> Hi Paul
> During the research, I found a already existing tool to detect
> undefined Kconfig macro:
> scripts/checkkconfigsymbols.py. It is marvellous!
Nice! Maybe I should add this to torture.sh.
> By invoking ./scripts/checkkconfigsymbols.py > /tmp/log, I found
> following possibly undefined Kconfig macros
> which may need our attention:
>
> PREEMPT_LOCK
> Referencing files: include/linux/lockdep_types.h
Not sure about this one. It might be in anticipation of -rt functionality.
Or another typo.
> PREEMT_DYNAMIC
> Referencing files: kernel/entry/common.c
This needs to be PREEMPT_DYNAMIC. Please CC Frederic Weisbecker and
myself if you send a patch.
> TREE_PREEMPT_RCU
> Referencing files: arch/sh/configs/sdk7786_defconfig
This would have been correct back in the day. It should now be
CONFIG_PREEMPT_RCU. Except that the CONFIG_PREEMPT=y in that same
file implies CONFIG_PREEMPT_RCU=y, so best to simply delete the
CONFIG_TREE_PREEMPT_RCU=y line.
> RCU_CPU_STALL_INFO
> Referencing files: arch/xtensa/configs/nommu_kc705_defconfig
You now get RCU_CPU_STALL_INFO whether you want it or not, so this
line should be deleted.
> RCU_NOCB_CPU_ALL
> Referencing files:
> Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst
This is an old snapshot of the code. One approach would be to
update this from the real rcu_prepare_for_idle() function in
kernel/rcu/tree_plugin.h. The line numbers in the following paragraph
would need to be updated, but the figure is unaffected.
> RCU_TORTURE_TESTS
> Referencing files: kernel/rcu/rcutorture.c
The final "S" needs to be dropped.
> and finally the macro which drive me to do this research
>
> TASKS_RCU_TRACE
> Referencing files: include/linux/rcupdate.h, kernel/rcu/tree_plugin.h
The fix for this one is of course already queued.
Please CC me if you decide to create patches. Otherwise, let me know,
and I can produce fixes.
Thanx, Paul
> On Fri, Jul 16, 2021 at 2:09 AM Paul E. McKenney <paulmck@kernel.org> wrote:
> >
> > On Thu, Jul 15, 2021 at 04:45:04PM +0800, Zhouyi Zhou wrote:
> > > On Thu, Jul 15, 2021 at 11:51 AM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > >
> > > > On Wed, Jul 14, 2021 at 12:44:36PM +0800, Zhouyi Zhou wrote:
> > > > > On Tue, Jul 13, 2021 at 11:19 PM Paul E. McKenney <paulmck@kernel.org> wrote:
> > > > > >
> > > > > > On Tue, Jul 13, 2021 at 06:18:12AM -0700, Paul E. McKenney wrote:
> > > > > > > On Tue, Jul 13, 2021 at 09:09:04AM -0400, Mathieu Desnoyers wrote:
> > > > > > > > ----- On Jul 13, 2021, at 12:16 AM, paulmck paulmck@kernel.org wrote:
> > > > > > > >
> > > > > > > > > On Tue, Jul 13, 2021 at 08:56:45AM +0800, zhouzhouyi@gmail.com wrote:
> > > > > > > > >> From: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > > > >>
> > > > > > > > >> Hi Paul,
> > > > > > > > >>
> > > > > > > > >> During my studying of RCU, I did a grep in the kernel source tree.
> > > > > > > > >> I found there are 3 places where the macro name CONFIG_TASKS_RCU_TRACE
> > > > > > > > >> should be CONFIG_TASKS_TRACE_RCU instead.
> > > > > > > > >>
> > > > > > > > >> Without memory fencing, the idle/userspace task inspection may not
> > > > > > > > >> be so accurate.
> > > > > > > > >>
> > > > > > > > >> Thanks for your constant encouragement for my studying.
> > > > > > > > >>
> > > > > > > > >> Best Wishes
> > > > > > > > >> Zhouyi
> > > > > > > > >>
> > > > > > > > >> Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> > > > > > > > >
> > > > > > > > > Good eyes, and those could cause real bugs, so thank you!
> > > > > > > >
> > > > > > > > Hi Paul,
> > > > > > > >
> > > > > > > > This makes me wonder: what is missing testing-wise in rcutorture to
> > > > > > > > catch those issues with testing before they reach mainline ?
> > > > > > >
> > > > > > > My guess: Running on weakly ordered architectures. ;-)
> > > > > >
> > > > > > And another guess: A tool that identifies use of Kconfig options
> > > > > > that are not defined in any Kconfig* file.
> > > > > Based on Paul's second guess ;-), I did a small research, and I think
> > > > > the best answer is to modify scripts/checkpatch.pl. We modify checkpatch.pl
> > > > > to identify use of Kconfig options that are not defined in any Kconfig* file.
> > > > >
> > > > > As I am a C/C++ programmer, I would be glad to take some time to learn
> > > > > perl (checkpatch is implented in perl) first if no other volunteer is
> > > > > about to do it ;-)
> > > >
> > > > I haven't heard anyone else volunteer. ;-)
> > > >
> > > > Others might have opinions on where best to implement these checks,
> > > > but I must confess that I have not given it much thought.
> > > I recklessly cc the maintainers of checkpatch.pl without your
> > > permission to see others' opion,
> > > and I begin to study perl at the same time, after all, learning
> > > something is always good ;-)
> >
> > Works for me!
> >
> > Thanx, Paul
> Best Wishes
> Zhouyi
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
2021-07-18 21:08 ` Paul E. McKenney
@ 2021-07-20 1:39 ` Randy Dunlap
2021-07-20 2:07 ` Paul E. McKenney
0 siblings, 1 reply; 6+ messages in thread
From: Randy Dunlap @ 2021-07-20 1:39 UTC (permalink / raw)
To: paulmck, Zhouyi Zhou
Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan,
Joel Fernandes, Google, rcu, linux-kernel, apw, joe, ast, daniel,
andrii, kafai, songliubraving, yhs, john.fastabend, kpsingh, bpf,
mingo
On 7/18/21 2:08 PM, Paul E. McKenney wrote:
> On Sun, Jul 18, 2021 at 06:03:34AM +0800, Zhouyi Zhou wrote:
>> Hi Paul
>> During the research, I found a already existing tool to detect
>> undefined Kconfig macro:
>> scripts/checkkconfigsymbols.py. It is marvellous!
>
> Nice! Maybe I should add this to torture.sh.
>
Paul, I believe that subsystems should take care of themselves,
so you can do that for RCU, e.g., but at the same time, I think that
some CI should be running that script (and other relevant scripts)
on the entire kernel tree and reporting problems that are found.
--
~Randy
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE
2021-07-20 1:39 ` Randy Dunlap
@ 2021-07-20 2:07 ` Paul E. McKenney
0 siblings, 0 replies; 6+ messages in thread
From: Paul E. McKenney @ 2021-07-20 2:07 UTC (permalink / raw)
To: Randy Dunlap
Cc: Zhouyi Zhou, Mathieu Desnoyers, Josh Triplett, rostedt,
Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel, apw,
joe, ast, daniel, andrii, kafai, songliubraving, yhs,
john.fastabend, kpsingh, bpf, mingo
On Mon, Jul 19, 2021 at 06:39:17PM -0700, Randy Dunlap wrote:
> On 7/18/21 2:08 PM, Paul E. McKenney wrote:
> > On Sun, Jul 18, 2021 at 06:03:34AM +0800, Zhouyi Zhou wrote:
> >> Hi Paul
> >> During the research, I found a already existing tool to detect
> >> undefined Kconfig macro:
> >> scripts/checkkconfigsymbols.py. It is marvellous!
> >
> > Nice! Maybe I should add this to torture.sh.
>
> Paul, I believe that subsystems should take care of themselves,
> so you can do that for RCU, e.g., but at the same time, I think that
> some CI should be running that script (and other relevant scripts)
> on the entire kernel tree and reporting problems that are found.
Even better! ;-)
Thanx, Paul
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-07-15 8:45 ` [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE Zhouyi Zhou
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2021-07-17 22:03 ` Zhouyi Zhou
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