From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Marco Elver <elver@google.com>
Cc: Mike Galbraith <efault@gmx.de>,
RT <linux-rt-users@vger.kernel.org>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
kasan-dev@googlegroups.com
Subject: Re: v5.19-rc2-rt3: mm/kfence might_sleep() splat
Date: Fri, 24 Jun 2022 11:19:43 +0200 [thread overview]
Message-ID: <YrWBr+jiFyZRLufc@linutronix.de> (raw)
In-Reply-To: <CANpmjNO+4uHo8sECw4e+hANQSHP+5UmFrZ2TgeRCsu2iuowYfw@mail.gmail.com>
On 2022-06-24 11:10:55 [+0200], Marco Elver wrote:
> On Fri, 24 Jun 2022 at 11:05, Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
> >
> > On 2022-06-18 11:34:51 [+0200], Mike Galbraith wrote:
> > > I moved the prandom_u32_max() call in kfence_guarded_alloc() out from
> > > under raw spinlock to shut this one up.
> >
> > Care to send a patch? I don't even why kfence_metadata::lock is a
> > raw_spinlock_t. This is the case since the beginning of the code.
>
> Because kfence_handle_page_fault() may be called from anywhere, incl.
> other raw_spinlock critical sections. We have this problem with all
> debugging tools where the bug may manifest anywhere.
Oh thank you. I had some vague memory of this but could find anything.
> A patch for it already exists in -mm:
> https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git/commit/?h=mm-hotfixes-stable&id=327b18b7aaed5de3b548212e3ab75133bf323759
Thanks for the pointer.
Sebastian
prev parent reply other threads:[~2022-06-24 9:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-18 9:34 v5.19-rc2-rt3: mm/kfence might_sleep() splat Mike Galbraith
2022-06-24 9:05 ` Sebastian Andrzej Siewior
2022-06-24 9:10 ` Marco Elver
2022-06-24 9:19 ` Sebastian Andrzej Siewior [this message]
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