linux-kernel - Re: workqueue deadlock

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]

Date:	Sat, 9 Dec 2006 11:26:52 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Andrew Morton <akpm@...l.org>
Cc:	vatsa@...ibm.com, Bjorn Helgaas <bjorn.helgaas@...com>,
	linux-kernel@...r.kernel.org, Myron Stowe <myron.stowe@...com>,
	Jens Axboe <axboe@...nel.dk>, Dipankar <dipankar@...ibm.com>,
	Gautham shenoy <ego@...ibm.com>
Subject: Re: workqueue deadlock


* Andrew Morton <akpm@...l.org> wrote:

> > > +		if (cpu != -1)
> > > +			mutex_lock(&workqueue_mutex);
> > 
> > events/4 thread itself wanting the same mutex above?
> 
> Could do, not sure.  I'm planning on converting all the locking around 
> here to preempt_disable() though.

please at least use an owner-recursive per-CPU lock, not a naked 
preempt_disable()! The concurrency rules for data structures changed via 
preempt_disable() are quite hard to sort out after the fact. 
(preempt_disable() is too opaque, it doesnt attach data structure to 
critical section, like normal locks do.)

	Ingo
-
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/