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From: Byungchul Park <byungchul.park@lge.com>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "mingo@kernel.org" <mingo@kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"amir73il@gmail.com" <amir73il@gmail.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"oleg@redhat.com" <oleg@redhat.com>,
	"darrick.wong@oracle.com" <darrick.wong@oracle.com>,
	"johannes.berg@intel.com" <johannes.berg@intel.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"idryomov@gmail.com" <idryomov@gmail.com>,
	"tj@kernel.org" <tj@kernel.org>,
	"kernel-team@lge.com" <kernel-team@lge.com>,
	"david@fromorbit.com" <david@fromorbit.com>
Subject: Re: [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map
Date: Fri, 20 Oct 2017 15:14:06 +0900	[thread overview]
Message-ID: <20171020061406.GF3310@X58A-UD3R> (raw)
In-Reply-To: <1508455438.4542.4.camel@wdc.com>

On Thu, Oct 19, 2017 at 11:24:00PM +0000, Bart Van Assche wrote:
> Are there any completion objects for which the cross-release checking is
> useful? Are there any wait_for_completion() callers that hold a mutex or
> other locking object?

Check /proc/lockdep, then you can find all dependencies wrt cross-lock.
I named a lock class of wait_for_completion(), a sting starting with
"(complete)".

For example, in my machine:

console_lock -> (complete)&req.done
cpu_hotplug_lock.rw_sem -> (complete)&st->done_up
cpuhp_state_mutex -> (complete)&st->done_up

and so on.

WARNING: multiple messages have this Message-ID (diff)
From: Byungchul Park <byungchul.park@lge.com>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "mingo@kernel.org" <mingo@kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"amir73il@gmail.com" <amir73il@gmail.com>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"oleg@redhat.com" <oleg@redhat.com>,
	"darrick.wong@oracle.com" <darrick.wong@oracle.com>,
	"johannes.berg@intel.com" <johannes.berg@intel.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"idryomov@gmail.com" <idryomov@gmail.com>,
	"tj@kernel.org" <tj@kernel.org>,
	"kernel-team@lge.com" <kernel-team@lge.com>,
	"david@fromorbit.com" <david@fromorbit.com>
Subject: Re: [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map
Date: Fri, 20 Oct 2017 15:14:06 +0900	[thread overview]
Message-ID: <20171020061406.GF3310@X58A-UD3R> (raw)
In-Reply-To: <1508455438.4542.4.camel@wdc.com>

On Thu, Oct 19, 2017 at 11:24:00PM +0000, Bart Van Assche wrote:
> Are there any completion objects for which the cross-release checking is
> useful? Are there any wait_for_completion() callers that hold a mutex or
> other locking object?

Check /proc/lockdep, then you can find all dependencies wrt cross-lock.
I named a lock class of wait_for_completion(), a sting starting with
"(complete)".

For example, in my machine:

console_lock -> (complete)&req.done
cpu_hotplug_lock.rw_sem -> (complete)&st->done_up
cpuhp_state_mutex -> (complete)&st->done_up

and so on.

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  reply	other threads:[~2017-10-20  6:14 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-18  9:38 Fix false positive by LOCKDEP_CROSSRELEASE Byungchul Park
2017-10-18  9:38 ` Byungchul Park
2017-10-18  9:38 ` [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map Byungchul Park
2017-10-18  9:38   ` Byungchul Park
2017-10-19 23:24   ` Bart Van Assche
2017-10-19 23:24     ` Bart Van Assche
2017-10-20  6:14     ` Byungchul Park [this message]
2017-10-20  6:14       ` Byungchul Park
2017-10-20  6:34     ` Thomas Gleixner
2017-10-20  6:34       ` Thomas Gleixner
2017-10-20 19:58       ` Bart Van Assche
2017-10-20 19:58         ` Bart Van Assche
2017-10-20 19:58         ` Bart Van Assche
2017-10-21  2:23         ` Byungchul Park
2017-10-21  2:23           ` Byungchul Park
2017-10-22 14:34           ` Bart Van Assche
2017-10-22 14:34             ` Bart Van Assche
2017-10-23  2:08             ` Byungchul Park
2017-10-23  2:08               ` Byungchul Park
2017-10-25  7:07               ` Bart Van Assche
2017-10-25  7:07                 ` Bart Van Assche
2017-10-25 11:49                 ` Byungchul Park
2017-10-25 11:49                   ` Byungchul Park
2017-10-18  9:38 ` [RESEND PATCH 2/3] lockdep: Remove unnecessary acquisitions wrt workqueue flush Byungchul Park
2017-10-18  9:38   ` Byungchul Park
2017-10-18  9:38 ` [RESEND PATCH 3/3] lockdep: Assign a lock_class per gendisk used for wait_for_completion() Byungchul Park
2017-10-18  9:38   ` Byungchul Park
2017-10-18  9:59   ` Ingo Molnar
2017-10-18  9:59     ` Ingo Molnar
2017-10-19  1:57     ` Byungchul Park
2017-10-19  1:57       ` Byungchul Park
2017-10-18 14:29 ` Fix false positive by LOCKDEP_CROSSRELEASE Bart Van Assche
2017-10-18 14:29   ` Bart Van Assche
2017-10-19  1:57   ` Byungchul Park
2017-10-19  1:57     ` Byungchul Park
2017-10-19 14:52     ` Bart Van Assche
2017-10-19 14:52       ` Bart Van Assche
2017-10-19 14:52       ` Bart Van Assche

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