linux-kernel - Re: [PATCH PREEMPT RT] rt-mutex: fix deadlock in device mapper

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:   Tue, 21 Nov 2017 04:20:30 +0100
From:   Mike Galbraith <efault@....de>
To:     Mikulas Patocka <mpatocka@...hat.com>
Cc:     Sebastian Siewior <bigeasy@...utronix.de>,
        linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-rt-users@...r.kernel.org
Subject: Re: [PATCH PREEMPT RT] rt-mutex: fix deadlock in device mapper

On Mon, 2017-11-20 at 16:33 -0500, Mikulas Patocka wrote:
> 
> Is there some specific scenario where you need to call 
> blk_schedule_flush_plug from rt_spin_lock_fastlock?

Excellent question.  What's the difference between not getting IO
started because you meet a mutex with an rt_mutex under the hood, and
not getting IO started because you meet a spinlock with an rt_mutex
under the hood?  If just doing the mutex side puts this thing back to
sleep, I'm happy.

	-Mike