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Date: Wed, 1 Feb 2017 10:37:39 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Ross Zwisler <zwisler@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Petr Mladek <pmladek@suse.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tejun Heo <tj@kernel.org>, Calvin Owens <calvinowens@fb.com>,
        Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Hurley <peter@hurleysoftware.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCHv7 6/8] printk: use printk_safe buffers in printk
Message-ID: <20170201093739.GT6515@twins.programming.kicks-ass.net>
References: <20161227141611.940-1-sergey.senozhatsky@gmail.com>
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On Wed, Feb 01, 2017 at 10:06:25AM +0100, Jan Kara wrote:
> Clearly scheduler code (update_load_avg) calls WARN_ON from scheduler while
> holding rq_lock which has been always forbidden. Sergey and Petr were doing
> some work to prevent similar deadlocks but I'm not sure how far they
> went...

Its not forbidden, just can result in the occasional deadlock, meh.


In any case, there's a patch in tip fixing that warn trigger.