Date: Mon, 11 Dec 2017 10:19:28 +0100
From: Daniel Vetter <daniel@ffwll.ch>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
        LKML <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        Tvrtko Ursulin <tvrtko.ursulin@intel.com>,
        Marta Lofstedt <marta.lofstedt@intel.com>,
        Byungchul Park <byungchul.park@lge.com>,
        Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>, Shaohua Li <shli@fb.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>, Oleg Nesterov <oleg@redhat.com>,
        Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] kthread: finer-grained lockdep/cross-release completion
Message-ID: <20171211091928.cpw3srz2rddmruxj@phenom.ffwll.local>
Mail-Followup-To: Peter Zijlstra <peterz@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        Tvrtko Ursulin <tvrtko.ursulin@intel.com>,
        Marta Lofstedt <marta.lofstedt@intel.com>,
        Byungchul Park <byungchul.park@lge.com>,
        Ingo Molnar <mingo@kernel.org>, Tejun Heo <tj@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Thomas Gleixner <tglx@linutronix.de>, Shaohua Li <shli@fb.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>, Oleg Nesterov <oleg@redhat.com>,
        Daniel Vetter <daniel.vetter@intel.com>
References: <20171207100849.407-1-daniel.vetter@ffwll.ch>
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On Fri, Dec 08, 2017 at 11:54:19AM +0100, Peter Zijlstra wrote:
> On Thu, Dec 07, 2017 at 11:08:49AM +0100, Daniel Vetter wrote:
> > Since -rc1 we're hitting a bunch of lockdep splats using the new
> > cross-release stuff around the 2 kthread completions. In all cases
> > they are because totally independent uses of kthread are mixed up by
> > lockdep into the same locking class, creating artificial deadlocks.
> > 
> > Fix this by converting kthread code in the same way as e.g.
> > alloc_workqueue already works: Use macros for the public api so we can
> > have a callsite specific lockdep key, then pass that through the
> > entire callchain. Due to the many entry points this is slightly
> > tedious.
> > 
> > Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> > Cc: Marta Lofstedt <marta.lofstedt@intel.com>
> > Cc: Byungchul Park <byungchul.park@lge.com>
> > Cc: Ingo Molnar <mingo@kernel.org>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Tejun Heo <tj@kernel.org>
> > Cc: Kees Cook <keescook@chromium.org>
> > Cc: Thomas Gleixner <tglx@linutronix.de>
> > Cc: Shaohua Li <shli@fb.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Jens Axboe <axboe@kernel.dk>
> > Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: Jonathan Corbet <corbet@lwn.net>
> > Cc: Oleg Nesterov <oleg@redhat.com>
> > References: https://bugs.freedesktop.org/show_bug.cgi?id=103950
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> 
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

Who's going to pick this up? Ingo, Andrew?

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch