37 lines
1.4 KiB
Diff
37 lines
1.4 KiB
Diff
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 21 Sep 2017 14:25:13 +0200
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Subject: [PATCH] RCU: we need to skip that warning but only on sleeping
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locks
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.14/older/patches-4.14.15-rt13.tar.xz
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This check is okay for upstream. On RT we trigger this while blocking on
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sleeping lock. In this case, it is okay to schedule() within a RCU
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section.
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Since spin_lock() and read_lock() disables migration it should be okay
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to test for this as an indication whether or not a sleeping lock is
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held. The ->pi_blocked_on member won't work becasuse it might also be
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set on regular mutexes.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/rcu/tree_plugin.h | 6 +++++-
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1 file changed, 5 insertions(+), 1 deletion(-)
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--- a/kernel/rcu/tree_plugin.h
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+++ b/kernel/rcu/tree_plugin.h
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@@ -323,9 +323,13 @@ static void rcu_preempt_note_context_swi
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struct task_struct *t = current;
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struct rcu_data *rdp;
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struct rcu_node *rnp;
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+ int mg_counter = 0;
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RCU_LOCKDEP_WARN(!irqs_disabled(), "rcu_preempt_note_context_switch() invoked with interrupts enabled!!!\n");
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- WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0);
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+#if defined(CONFIG_PREEMPT_COUNT) && defined(CONFIG_SMP)
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+ mg_counter = t->migrate_disable;
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+#endif
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+ WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !mg_counter);
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if (t->rcu_read_lock_nesting > 0 &&
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!t->rcu_read_unlock_special.b.blocked) {
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