* [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE @ 2021-07-13 0:56 zhouzhouyi 2021-07-13 4:16 ` Paul E. McKenney 0 siblings, 1 reply; 14+ messages in thread From: zhouzhouyi @ 2021-07-13 0:56 UTC (permalink / raw) To: paulmck, josh, rostedt, mathieu.desnoyers, jiangshanlai, joel, rcu, linux-kernel Cc: Zhouyi Zhou 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> --- include/linux/rcupdate.h | 2 +- kernel/rcu/tree_plugin.h | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d9680b798b21..955c82b4737c 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -167,7 +167,7 @@ void synchronize_rcu_tasks(void); # define synchronize_rcu_tasks synchronize_rcu # endif -# ifdef CONFIG_TASKS_RCU_TRACE +# ifdef CONFIG_TASKS_TRACE_RCU # define rcu_tasks_trace_qs(t) \ do { \ if (!likely(READ_ONCE((t)->trc_reader_checked)) && \ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index de1dc3bb7f70..6ce104242b23 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2982,17 +2982,17 @@ static void noinstr rcu_dynticks_task_exit(void) /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */ static void rcu_dynticks_task_trace_enter(void) { -#ifdef CONFIG_TASKS_RCU_TRACE +#ifdef CONFIG_TASKS_TRACE_RCU if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) current->trc_reader_special.b.need_mb = true; -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ } /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */ static void rcu_dynticks_task_trace_exit(void) { -#ifdef CONFIG_TASKS_RCU_TRACE +#ifdef CONFIG_TASKS_TRACE_RCU if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) current->trc_reader_special.b.need_mb = false; -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ } -- 2.25.1 ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 0:56 [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE zhouzhouyi @ 2021-07-13 4:16 ` Paul E. McKenney 2021-07-13 6:16 ` Zhouyi Zhou 2021-07-13 13:09 ` Mathieu Desnoyers 0 siblings, 2 replies; 14+ messages in thread From: Paul E. McKenney @ 2021-07-13 4:16 UTC (permalink / raw) To: zhouzhouyi Cc: josh, rostedt, mathieu.desnoyers, jiangshanlai, joel, rcu, linux-kernel 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! Could you please check the wordsmithed version below? Thanx, Paul ------------------------------------------------------------------------ commit fdcf5524b64f2cc8e6201447644079d9f8d4c821 Author: Zhouyi Zhou <zhouzhouyi@gmail.com> Date: Tue Jul 13 08:56:45 2021 +0800 RCU: Fix macro name CONFIG_TASKS_RCU_TRACE This commit fixes several typos where CONFIG_TASKS_RCU_TRACE should instead be CONFIG_TASKS_TRACE_RCU. Among other things, these typos could cause CONFIG_TASKS_TRACE_RCU_READ_MB=y kernels to suffer from memory-ordering bugs that could result in false-positive quiescent states and too-short grace periods. Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index cfeb43bfc719..434d12fe2d4f 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -167,7 +167,7 @@ void synchronize_rcu_tasks(void); # define synchronize_rcu_tasks synchronize_rcu # endif -# ifdef CONFIG_TASKS_RCU_TRACE +# ifdef CONFIG_TASKS_TRACE_RCU # define rcu_tasks_trace_qs(t) \ do { \ if (!likely(READ_ONCE((t)->trc_reader_checked)) && \ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 27b74352cccf..a8e3acead6f6 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1498,17 +1498,17 @@ static void noinstr rcu_dynticks_task_exit(void) /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */ static void rcu_dynticks_task_trace_enter(void) { -#ifdef CONFIG_TASKS_RCU_TRACE +#ifdef CONFIG_TASKS_TRACE_RCU if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) current->trc_reader_special.b.need_mb = true; -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ } /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */ static void rcu_dynticks_task_trace_exit(void) { -#ifdef CONFIG_TASKS_RCU_TRACE +#ifdef CONFIG_TASKS_TRACE_RCU if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) current->trc_reader_special.b.need_mb = false; -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ } ^ permalink raw reply related [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 4:16 ` Paul E. McKenney @ 2021-07-13 6:16 ` Zhouyi Zhou 2021-07-13 13:09 ` Mathieu Desnoyers 1 sibling, 0 replies; 14+ messages in thread From: Zhouyi Zhou @ 2021-07-13 6:16 UTC (permalink / raw) To: paulmck Cc: josh, rostedt, mathieu.desnoyers, jiangshanlai, joel, rcu, linux-kernel Thank you very much, I went through the wordsmithed version, it looks exquisite! Thank you for your encouragement. Cheers Zhouyi On Tue, Jul 13, 2021 at 12:16 PM Paul E. McKenney <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! > > Could you please check the wordsmithed version below? > > Thanx, Paul > > ------------------------------------------------------------------------ > > commit fdcf5524b64f2cc8e6201447644079d9f8d4c821 > Author: Zhouyi Zhou <zhouzhouyi@gmail.com> > Date: Tue Jul 13 08:56:45 2021 +0800 > > RCU: Fix macro name CONFIG_TASKS_RCU_TRACE > > This commit fixes several typos where CONFIG_TASKS_RCU_TRACE should > instead be CONFIG_TASKS_TRACE_RCU. Among other things, these typos > could cause CONFIG_TASKS_TRACE_RCU_READ_MB=y kernels to suffer from > memory-ordering bugs that could result in false-positive quiescent > states and too-short grace periods. > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index cfeb43bfc719..434d12fe2d4f 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -167,7 +167,7 @@ void synchronize_rcu_tasks(void); > # define synchronize_rcu_tasks synchronize_rcu > # endif > > -# ifdef CONFIG_TASKS_RCU_TRACE > +# ifdef CONFIG_TASKS_TRACE_RCU > # define rcu_tasks_trace_qs(t) \ > do { \ > if (!likely(READ_ONCE((t)->trc_reader_checked)) && \ > diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h > index 27b74352cccf..a8e3acead6f6 100644 > --- a/kernel/rcu/tree_plugin.h > +++ b/kernel/rcu/tree_plugin.h > @@ -1498,17 +1498,17 @@ static void noinstr rcu_dynticks_task_exit(void) > /* Turn on heavyweight RCU tasks trace readers on idle/user entry. */ > static void rcu_dynticks_task_trace_enter(void) > { > -#ifdef CONFIG_TASKS_RCU_TRACE > +#ifdef CONFIG_TASKS_TRACE_RCU > if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) > current->trc_reader_special.b.need_mb = true; > -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ > +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ > } > > /* Turn off heavyweight RCU tasks trace readers on idle/user exit. */ > static void rcu_dynticks_task_trace_exit(void) > { > -#ifdef CONFIG_TASKS_RCU_TRACE > +#ifdef CONFIG_TASKS_TRACE_RCU > if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB)) > current->trc_reader_special.b.need_mb = false; > -#endif /* #ifdef CONFIG_TASKS_RCU_TRACE */ > +#endif /* #ifdef CONFIG_TASKS_TRACE_RCU */ > } ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 4:16 ` Paul E. McKenney 2021-07-13 6:16 ` Zhouyi Zhou @ 2021-07-13 13:09 ` Mathieu Desnoyers 2021-07-13 13:18 ` Paul E. McKenney 1 sibling, 1 reply; 14+ messages in thread From: Mathieu Desnoyers @ 2021-07-13 13:09 UTC (permalink / raw) To: paulmck Cc: zhouzhouyi, Josh Triplett, rostedt, Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel ----- 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 ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 13:09 ` Mathieu Desnoyers @ 2021-07-13 13:18 ` Paul E. McKenney 2021-07-13 15:19 ` Paul E. McKenney 0 siblings, 1 reply; 14+ messages in thread From: Paul E. McKenney @ 2021-07-13 13:18 UTC (permalink / raw) To: Mathieu Desnoyers Cc: zhouzhouyi, Josh Triplett, rostedt, Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel 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. ;-) Thanx, Paul ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 13:18 ` Paul E. McKenney @ 2021-07-13 15:19 ` Paul E. McKenney 2021-07-14 4:44 ` Zhouyi Zhou 0 siblings, 1 reply; 14+ messages in thread From: Paul E. McKenney @ 2021-07-13 15:19 UTC (permalink / raw) To: Mathieu Desnoyers Cc: zhouzhouyi, Josh Triplett, rostedt, Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel 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. Thanx, Paul ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-13 15:19 ` Paul E. McKenney @ 2021-07-14 4:44 ` Zhouyi Zhou 2021-07-15 3:51 ` Paul E. McKenney 0 siblings, 1 reply; 14+ messages in thread From: Zhouyi Zhou @ 2021-07-14 4:44 UTC (permalink / raw) To: paulmck Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel 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 ;-) > > Thanx, Paul Thanx Zhouyi ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-14 4:44 ` Zhouyi Zhou @ 2021-07-15 3:51 ` Paul E. McKenney 2021-07-15 8:45 ` Zhouyi Zhou 0 siblings, 1 reply; 14+ messages in thread From: Paul E. McKenney @ 2021-07-15 3:51 UTC (permalink / raw) To: Zhouyi Zhou Cc: Mathieu Desnoyers, Josh Triplett, rostedt, Lai Jiangshan, Joel Fernandes, Google, rcu, linux-kernel 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. Thanx, Paul ^ permalink raw reply [flat|nested] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-15 3:51 ` Paul E. McKenney @ 2021-07-15 8:45 ` Zhouyi Zhou 2021-07-15 18:09 ` Paul E. McKenney 0 siblings, 1 reply; 14+ 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] 14+ messages in thread
* Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE 2021-07-15 8:45 ` Zhouyi Zhou @ 2021-07-15 18:09 ` Paul E. McKenney 2021-07-17 22:03 ` Zhouyi Zhou 0 siblings, 1 reply; 14+ 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] 14+ 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; 14+ 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] 14+ 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; 14+ 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] 14+ 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; 14+ 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] 14+ 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; 14+ 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] 14+ messages in thread
end of thread, other threads:[~2021-07-20 2:11 UTC | newest] Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-07-13 0:56 [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE zhouzhouyi 2021-07-13 4:16 ` Paul E. McKenney 2021-07-13 6:16 ` Zhouyi Zhou 2021-07-13 13:09 ` Mathieu Desnoyers 2021-07-13 13:18 ` Paul E. McKenney 2021-07-13 15:19 ` Paul E. McKenney 2021-07-14 4:44 ` Zhouyi Zhou 2021-07-15 3:51 ` Paul E. McKenney 2021-07-15 8:45 ` Zhouyi Zhou 2021-07-15 18:09 ` Paul E. McKenney 2021-07-17 22:03 ` Zhouyi Zhou 2021-07-18 21:08 ` Paul E. McKenney 2021-07-20 1:39 ` Randy Dunlap 2021-07-20 2:07 ` Paul E. McKenney
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