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Date:   Mon, 19 Oct 2020 17:29:09 +0200
From:   Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Minchan Kim <minchan@kernel.org>,
        Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        linux-block@vger.kernel.org,
        Mike Galbraith <umgwanakikbuti@gmail.com>, ngupta@vflare.org,
        sergey.senozhatsky.work@gmail.com,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] zram: Fix __zram_bvec_{read,write}() locking order
Message-ID: <20201019152909.rlnhqokqhhauq2kw@linutronix.de>
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On 2020-10-19 12:13:53 [+0200], Peter Zijlstra wrote:
> 
> Mikhail reported a lockdep spat detailing how __zram_bvec_read() and
> __zram_bvec_write() use zstrm->lock and zspage->lock in opposite order.
> 
> Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>

We have the same patch in RT. I didn't submit it with the other
local-lock patches because this splat pops up once pin_tag() is made a
sleeping lock. I missed the part where migrate_read_lock() can be a
lock. So:

Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Sebastian