linux-kernel - Re: [PATCH v3] kunit: added lockdep support

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: <CAG30Eef1RBj07_=KCJ5G2J0k3_pgL-hM6PiYba0Vf6O16WhnUQ@mail.gmail.com>
Date:   Fri, 14 Aug 2020 16:00:06 -0500
From:   Uriel Guajardo <urielguajardo@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Uriel Guajardo <urielguajardojr@...il.com>,
        Brendan Higgins <brendanhiggins@...gle.com>, mingo@...hat.com,
        will@...nel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@...r.kernel.org>,
        KUnit Development <kunit-dev@...glegroups.com>,
        Alan Maguire <alan.maguire@...cle.com>
Subject: Re: [PATCH v3] kunit: added lockdep support

On Fri, Aug 14, 2020 at 3:58 PM Peter Zijlstra <peterz@...radead.org> wrote:
>
> On Fri, Aug 14, 2020 at 08:55:27PM +0000, Uriel Guajardo wrote:
> > +
> > +void kunit_check_lockdep(struct kunit *test, struct kunit_lockdep *lockdep) {
> > +     int saved_preempt_count = lockdep->preempt_count;
> > +     bool saved_debug_locks = lockdep->debug_locks;
> > +
> > +     if (DEBUG_LOCKS_WARN_ON(preempt_count() != saved_preempt_count))
> > +             preempt_count_set(saved_preempt_count);
> > +
> > +#ifdef CONFIG_TRACE_IRQFLAGS
> > +     if (softirq_count())
> > +             current->softirqs_enabled = 0;
> > +     else
> > +             current->softirqs_enabled = 1;
> > +#endif
>
> This block is pointless. The only way to get softirq tracing out of sync
> is an unbalanced local_bh_disable(), but then the above preempt_count()
> test will trigger and kill IRQ tracing.

Ahh I see. Thank you.

>
> > +
> > +     if (saved_debug_locks && !debug_locks) {
> > +             kunit_set_failure(test);
> > +             kunit_warn(test, "Dynamic analysis tool failure from LOCKDEP.");
> > +             kunit_warn(test, "Further tests will have LOCKDEP disabled.");
> > +     }
> > +}