linux-kernel - Re: [PATCH v2 1/9] Coccinelle: locks: identify callers of spin_lock{,_irq,

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: <20170322161856.GJ10423@jcartwri.amer.corp.natinst.com>
Date:   Wed, 22 Mar 2017 11:18:56 -0500
From:   Julia Cartwright <julia@...com>
To:     Julia Lawall <julia.lawall@...6.fr>
CC:     Gilles Muller <Gilles.Muller@...6.fr>,
        Nicolas Palix <nicolas.palix@...g.fr>,
        Michal Marek <mmarek@...e.com>, <linux-kernel@...r.kernel.org>,
        <linux-rt-users@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        <cocci@...teme.lip6.fr>
Subject: Re: [PATCH v2 1/9] Coccinelle: locks: identify callers of
 spin_lock{,_irq,_irqsave}() in irqchip implementations

On Wed, Mar 22, 2017 at 10:54:15AM +0100, Julia Lawall wrote:
> On Tue, 21 Mar 2017, Julia Cartwright wrote:
> > On PREEMPT_RT, the spinlock_t type becomes an object which sleeps under
> > contention.  The codepaths used to support scheduling (irq dispatching, arch
> > code, the scheduler, timers) therefore must make use of the
> > raw_spin_lock{,_irq,_irqsave}() variations which preserve the non-sleeping
> > spinlock behavior.
> >
> > Because the irq_chip callbacks are invoked in the process of interrupt
> > dispatch, they cannot therefore make use of spin_lock_t type.  Instead, the
> > usage of raw_spinlock_t is appropriate.
> >
> > Provide a spatch to identify (and attempt to patch) such problematic irqchip
> > implementations.
> >
> > Note to those generating patches using this spatch; in order to maintain
> > correct semantics w/ PREEMPT_RT, it is necessary to audit the
> > raw_spinlock_t-protected codepaths to ensure their execution is bounded and
> > minimal.  This is a manual audit process.
> >
> > See commit 47b03ca903fb0 ("pinctrl: qcom: Use raw spinlock variants") as an
> > example of _one_ such instance, which fixed a real bug seen in the field.
> >
> > Cc: Thomas Gleixner <tglx@...utronix.de>
> > Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> > Cc: Linus Walleij <linus.walleij@...aro.org>
> > Signed-off-by: Julia Cartwright <julia@...com>
> 
> Acked-by: Julia Lawall <julia.lawall@...6.fr>

Thanks, Julia.

How do these semantic patches normally land?  It looks like they quite a
few have gone through the kbuild tree, is this the norm?

Thanks,
   Other Julia