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From: Peter Zijlstra <peterz@infradead.org>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
	tip-bot2 for Peter Zijlstra <tip-bot2@linutronix.de>,
	Qian Cai <cai@redhat.com>, x86 <x86@kernel.org>
Subject: Re: [tip: locking/core] lockdep: Fix usage_traceoverflow
Date: Tue, 27 Oct 2020 13:48:34 +0100	[thread overview]
Message-ID: <20201027124834.GL2628@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201027123056.GE2651@hirez.programming.kicks-ass.net>

On Tue, Oct 27, 2020 at 01:30:56PM +0100, Peter Zijlstra wrote:
> This seems to make it happy. Not quite sure that's the best solution.
> 
> diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
> index 3e99dfef8408..81295bc760fe 100644
> --- a/kernel/locking/lockdep.c
> +++ b/kernel/locking/lockdep.c
> @@ -4411,7 +4405,9 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
>  		break;
>  
>  	case LOCK_USED:
> -		debug_atomic_dec(nr_unused_locks);
> +	case LOCK_USED_READ:
> +		if ((hlock_class(this)->usage_mask & (LOCKF_USED|LOCKF_USED_READ)) == new_mask)
> +			debug_atomic_dec(nr_unused_locks);
>  		break;
>  
>  	default:

This also works, and I think I likes it better.. anyone?

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 3e99dfef8408..e603e86c0227 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4396,6 +4390,9 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 	if (unlikely(hlock_class(this)->usage_mask & new_mask))
 		goto unlock;
 
+	if (!hlock_class(this)->usage_mask)
+		debug_atomic_dec(nr_unused_locks);
+
 	hlock_class(this)->usage_mask |= new_mask;
 
 	if (new_bit < LOCK_TRACE_STATES) {
@@ -4403,19 +4400,10 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
 			return 0;
 	}
 
-	switch (new_bit) {
-	case 0 ... LOCK_USED-1:
+	if (new_bit < LOCK_USED) {
 		ret = mark_lock_irq(curr, this, new_bit);
 		if (!ret)
 			return 0;
-		break;
-
-	case LOCK_USED:
-		debug_atomic_dec(nr_unused_locks);
-		break;
-
-	default:
-		break;
 	}
 
 unlock:



  reply	other threads:[~2020-10-27 12:48 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-29 14:31 lockdep null-ptr-deref Qian Cai
2020-09-29 23:08 ` Boqun Feng
2020-09-30  9:16   ` Peter Zijlstra
2020-09-30  9:49     ` Peter Zijlstra
2020-09-30 12:18       ` Boqun Feng
2020-09-30 19:02         ` Peter Zijlstra
2020-10-02 12:36           ` Boqun Feng
2020-10-02 13:09             ` Peter Zijlstra
2020-10-02 13:35               ` Boqun Feng
2020-10-02 10:06       ` Peter Zijlstra
2020-10-02 13:40         ` Qian Cai
2020-10-07 16:20       ` [tip: locking/core] lockdep: Fix usage_traceoverflow tip-bot2 for Peter Zijlstra
2020-10-27 11:29         ` Chris Wilson
2020-10-27 11:59           ` Peter Zijlstra
2020-10-27 12:30             ` Peter Zijlstra
2020-10-27 12:48               ` Peter Zijlstra [this message]
2020-10-27 14:13                 ` Chris Wilson
2020-10-31 11:30                 ` [tip: locking/urgent] lockdep: Fix nr_unused_locks accounting tip-bot2 for Peter Zijlstra
2020-10-27 13:29               ` [tip: locking/core] lockdep: Fix usage_traceoverflow Chris Wilson
2020-10-27 15:45                 ` Peter Zijlstra
2020-10-27 16:34                   ` Chris Wilson
2020-10-28 17:40                     ` Chris Wilson
2020-10-28 18:06                       ` Chris Wilson
2020-10-28 19:42                       ` Peter Zijlstra
2020-10-28 19:59                         ` Peter Zijlstra
2020-10-30  3:51                           ` Boqun Feng
2020-10-30  9:38                             ` Peter Zijlstra
2020-10-30  9:55                               ` Peter Zijlstra
2020-11-02  5:37                               ` [PATCH 1/2] lockdep: Avoid to modify chain keys in validate_chain() Boqun Feng
2020-11-02  5:37                                 ` [PATCH 2/2] lockdep/selftest: Add spin_nest_lock test Boqun Feng
2020-12-03 10:35                                   ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-11-05  6:25                                 ` [PATCH 1/2] lockdep: Avoid to modify chain keys in validate_chain() Boqun Feng
2020-11-10 17:28                                 ` Peter Zijlstra
2020-11-11  8:23                                 ` [tip: locking/urgent] " tip-bot2 for Boqun Feng
2020-10-09  7:58       ` [tip: locking/core] lockdep: Fix usage_traceoverflow tip-bot2 for Peter Zijlstra

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