Date: Fri, 8 Dec 2017 11:54:19 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: 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: <20171208105419.jdzene5wrsriwm2n@hirez.programming.kicks-ass.net>
References: <20171207100849.407-1-daniel.vetter@ffwll.ch>
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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>