From: "tip-bot2 for Peter Zijlstra" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, x86 <x86@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [tip: locking/core] lockdep: Prepare for NMI IRQ state tracking
Date: Sat, 11 Jul 2020 10:09:57 -0000 [thread overview]
Message-ID: <159446219720.4006.9282048000882212758.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200623083721.155449112@infradead.org>
The following commit has been merged into the locking/core branch of tip:
Commit-ID: 859d069ee1ddd87862e1d6a356a82ed417dbeb67
Gitweb: https://git.kernel.org/tip/859d069ee1ddd87862e1d6a356a82ed417dbeb67
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 27 May 2020 15:00:57 +02:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 10 Jul 2020 12:00:01 +02:00
lockdep: Prepare for NMI IRQ state tracking
There is no reason not to always, accurately, track IRQ state.
This change also makes IRQ state tracking ignore lockdep_off().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200623083721.155449112@infradead.org
---
kernel/locking/lockdep.c | 46 +++++++++++++++++++++++++++++++++++----
1 file changed, 42 insertions(+), 4 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 29a8de4..d595623 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -395,7 +395,7 @@ void lockdep_init_task(struct task_struct *task)
static __always_inline void lockdep_recursion_finish(void)
{
- if (WARN_ON_ONCE(--current->lockdep_recursion))
+ if (WARN_ON_ONCE((--current->lockdep_recursion) & LOCKDEP_RECURSION_MASK))
current->lockdep_recursion = 0;
}
@@ -3646,7 +3646,16 @@ static void __trace_hardirqs_on_caller(void)
*/
void lockdep_hardirqs_on_prepare(unsigned long ip)
{
- if (unlikely(!debug_locks || current->lockdep_recursion))
+ if (unlikely(!debug_locks))
+ return;
+
+ /*
+ * NMIs do not (and cannot) track lock dependencies, nothing to do.
+ */
+ if (unlikely(in_nmi()))
+ return;
+
+ if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
return;
if (unlikely(current->hardirqs_enabled)) {
@@ -3692,7 +3701,27 @@ void noinstr lockdep_hardirqs_on(unsigned long ip)
{
struct task_struct *curr = current;
- if (unlikely(!debug_locks || curr->lockdep_recursion))
+ if (unlikely(!debug_locks))
+ return;
+
+ /*
+ * NMIs can happen in the middle of local_irq_{en,dis}able() where the
+ * tracking state and hardware state are out of sync.
+ *
+ * NMIs must save lockdep_hardirqs_enabled() to restore IRQ state from,
+ * and not rely on hardware state like normal interrupts.
+ */
+ if (unlikely(in_nmi())) {
+ /*
+ * Skip:
+ * - recursion check, because NMI can hit lockdep;
+ * - hardware state check, because above;
+ * - chain_key check, see lockdep_hardirqs_on_prepare().
+ */
+ goto skip_checks;
+ }
+
+ if (unlikely(current->lockdep_recursion & LOCKDEP_RECURSION_MASK))
return;
if (curr->hardirqs_enabled) {
@@ -3720,6 +3749,7 @@ void noinstr lockdep_hardirqs_on(unsigned long ip)
DEBUG_LOCKS_WARN_ON(current->hardirq_chain_key !=
current->curr_chain_key);
+skip_checks:
/* we'll do an OFF -> ON transition: */
curr->hardirqs_enabled = 1;
curr->hardirq_enable_ip = ip;
@@ -3735,7 +3765,15 @@ void noinstr lockdep_hardirqs_off(unsigned long ip)
{
struct task_struct *curr = current;
- if (unlikely(!debug_locks || curr->lockdep_recursion))
+ if (unlikely(!debug_locks))
+ return;
+
+ /*
+ * Matching lockdep_hardirqs_on(), allow NMIs in the middle of lockdep;
+ * they will restore the software state. This ensures the software
+ * state is consistent inside NMIs as well.
+ */
+ if (unlikely(!in_nmi() && (current->lockdep_recursion & LOCKDEP_RECURSION_MASK)))
return;
/*
next prev parent reply other threads:[~2020-07-11 10:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 8:36 [PATCH v4 0/8] lockdep: Change IRQ state tracking to use per-cpu variables Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 1/8] lockdep: Prepare for NMI IRQ state tracking Peter Zijlstra
2020-07-11 10:09 ` tip-bot2 for Peter Zijlstra [this message]
2020-06-23 8:36 ` [PATCH v4 2/8] x86/entry: Fix NMI vs " Peter Zijlstra
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 3/8] sparc64: Fix asm/percpu.h build error Peter Zijlstra
2020-06-23 21:35 ` David Miller
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 4/8] powerpc64: Break asm/percpu.h vs spinlock_types.h dependency Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 5/8] s390: Break cyclic percpu include Peter Zijlstra
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 6/8] arm: " Peter Zijlstra
2020-06-23 9:02 ` Will Deacon
2020-06-24 17:53 ` Peter Zijlstra
2020-06-25 7:31 ` Will Deacon
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 7/8] lockdep: Change hardirq{s_enabled,_context} to per-cpu variables Peter Zijlstra
2020-06-23 15:00 ` Ahmed S. Darwish
2020-06-23 15:24 ` Peter Zijlstra
2020-06-23 16:13 ` Ahmed S. Darwish
2020-06-23 16:37 ` Peter Zijlstra
2020-06-23 17:59 ` Marco Elver
2020-06-23 18:12 ` Peter Zijlstra
2020-06-23 18:39 ` Marco Elver
2020-06-23 19:13 ` Marco Elver
2020-06-23 19:41 ` Peter Zijlstra
2020-06-23 20:08 ` Peter Zijlstra
2020-06-23 20:24 ` Peter Zijlstra
2020-06-23 20:33 ` Peter Zijlstra
2020-06-24 9:00 ` Peter Zijlstra
2020-06-24 10:17 ` Marco Elver
2020-06-24 12:31 ` Peter Zijlstra
2020-06-24 11:32 ` Marco Elver
2020-06-24 15:18 ` Peter Zijlstra
2020-07-11 10:09 ` [tip: locking/core] kcsan: Make KCSAN compatible with new IRQ state tracking tip-bot2 for Marco Elver
2020-06-30 5:59 ` [PATCH v4 7/8] lockdep: Change hardirq{s_enabled,_context} to per-cpu variables Ahmed S. Darwish
2020-06-30 9:40 ` Peter Zijlstra
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2020-06-23 8:36 ` [PATCH v4 8/8] lockdep: Remove lockdep_hardirq{s_enabled,_context}() argument Peter Zijlstra
2020-07-11 10:09 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
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