linux-kernel - Re: [PATCH 2/2] ARC: show_regs: fix lockdep splat for good

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: <20181221132753.GB4842@dhcp22.suse.cz>
Date:   Fri, 21 Dec 2018 14:27:53 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Vineet Gupta <vineet.gupta1@...opsys.com>
Cc:     "linux-snps-arc@...ts.infradead.org" 
        <linux-snps-arc@...ts.infradead.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 2/2] ARC: show_regs: fix lockdep splat for good

On Fri 21-12-18 14:04:04, Michal Hocko wrote:
[...]
> Yes, but you are building on a broken concept I believe. What
> implications does re-enabling really have? Now you could reschedule and
> you can move to another CPU. Is this really safe? I believe that yes
> because the preemption disabling is simply bogus. Which doesn't sound
> like a proper justification, does it?

Well, thinking about it a bit more. What is the result of calling
preempt_enable outside of preempt_disabled section? E.g. __warn which
doesn't disable preemption AFAICS.
-- 
Michal Hocko
SUSE Labs