linux-kernel - Re: [PATCH 3/6] workqueue: make cancel_rearming_delayed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20070207151630.GA138@tv-sign.ru>
Date:	Wed, 7 Feb 2007 18:16:30 +0300
From:	Oleg Nesterov <oleg@...sign.ru>
To:	Daniel Drake <dsd@...too.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	David Howells <dhowells@...hat.com>
Subject: Re: [PATCH 3/6] workqueue: make cancel_rearming_delayed_workqueue() work on idle dwork

On 02/07, Daniel Drake wrote:
>
> Oleg Nesterov wrote:
> >cancel_rearming_delayed_workqueue(dwork) will hang forever if dwork was not
> >scheduled, because in that case cancel_delayed_work()->del_timer_sync() 
> >never
> >returns true.
> 
> Thanks! We hit this problem before with the zd1211rw driver and avoided 
> using cancel_rearming_delayed_workqueue() for this reason.

Great. But I am afraid my changelog was incomplete. This patch only fixes
the cancel_rearming_delayed_workqueue(freshly_initialized_dwork) lockup.

The following code

	schedule_delayed_work(dw);
	cancel_rearming_delayed_workqueue(dw);	// OK
	cancel_rearming_delayed_workqueue(dw);	// HANGS!

still doesn't work.

Is it worth fixing? The fix is very simple, and probably makes sense by
itself:

	cancel_delayed_work:

	-	work_release(&work->work);
	+	work->work.data = NULL;

Oleg.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/