Messages in this thread Patch in this message | | | Date | Mon, 12 Jul 2021 21:16:07 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] RCU: Fix macro name CONFIG_TASKS_RCU_TRACE |
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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
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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 */ }
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