From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, will@kernel.org, tglx@linutronix.de
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
a.darwish@linutronix.de, rostedt@goodmis.org,
bigeasy@linutronix.de, peterz@infradead.org
Subject: [PATCH 1/6] x86/entry: Clarify irq_{enter,exit}_rcu()
Date: Wed, 27 May 2020 17:45:28 +0200 [thread overview]
Message-ID: <20200527155003.131379869@infradead.org> (raw)
In-Reply-To: 20200527154527.233385756@infradead.org
Because:
irq_enter_rcu() includes lockdep_hardirq_enter()
irq_exit_rcu() does *NOT* include lockdep_hardirq_exit()
Which resulted two 'stray' lockdep_hardirq_exit() calls in idtentry.h,
and me spending a long time trying to find the matching enters.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/idtentry.h | 2 --
kernel/softirq.c | 19 +++++++++++++------
2 files changed, 13 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -206,7 +206,6 @@ __visible noinstr void func(struct pt_re
kvm_set_cpu_l1tf_flush_l1d(); \
__##func (regs, (u8)error_code); \
irq_exit_rcu(); \
- lockdep_hardirq_exit(); \
instrumentation_end(); \
idtentry_exit_cond_rcu(regs, rcu_exit); \
} \
@@ -249,7 +248,6 @@ __visible noinstr void func(struct pt_re
kvm_set_cpu_l1tf_flush_l1d(); \
run_on_irqstack_cond(__##func, regs, regs); \
irq_exit_rcu(); \
- lockdep_hardirq_exit(); \
instrumentation_end(); \
idtentry_exit_cond_rcu(regs, rcu_exit); \
} \
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -404,12 +404,7 @@ static inline void tick_irq_exit(void)
#endif
}
-/**
- * irq_exit_rcu() - Exit an interrupt context without updating RCU
- *
- * Also processes softirqs if needed and possible.
- */
-void irq_exit_rcu(void)
+static inline void __irq_exit_rcu(void)
{
#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
local_irq_disable();
@@ -425,6 +420,18 @@ void irq_exit_rcu(void)
}
/**
+ * irq_exit_rcu() - Exit an interrupt context without updating RCU
+ *
+ * Also processes softirqs if needed and possible.
+ */
+void irq_exit_rcu(void)
+{
+ __irq_exit_rcu();
+ /* must be last! */
+ lockdep_hardirq_exit();
+}
+
+/**
* irq_exit - Exit an interrupt context, update RCU and lockdep
*
* Also processes softirqs if needed and possible.
next prev parent reply other threads:[~2020-05-27 15:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 15:45 [PATCH 0/6] x86/entry,lockdep: Improve IRQ state tracking Peter Zijlstra
2020-05-27 15:45 ` Peter Zijlstra [this message]
2020-05-27 15:45 ` [PATCH 2/6] lockdep: Change hardirq{s_enabled,_context} to per-cpu variables Peter Zijlstra
2020-05-27 17:39 ` Peter Zijlstra
2020-05-27 15:45 ` [PATCH 3/6] lockdep: Remove lockdep_hardirq{s_enabled,_context}() argument Peter Zijlstra
2020-05-27 15:45 ` [PATCH 4/6] x86/entry: Rename trace_hardirqs_off_prepare() Peter Zijlstra
2020-05-27 15:45 ` [PATCH 5/6] lockdep: Prepare for NMI IRQ state tracking Peter Zijlstra
2020-05-27 15:45 ` [PATCH 6/6] x86/entry: Fix NMI vs " Peter Zijlstra
2020-05-27 16:43 ` [PATCH 0/6] x86/entry,lockdep: Improve " Peter Zijlstra
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