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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
Date: Mon, 19 Oct 2020 17:29:09 +0200	[thread overview]
Message-ID: <20201019152909.rlnhqokqhhauq2kw@linutronix.de> (raw)
In-Reply-To: <20201019101353.GJ2628@hirez.programming.kicks-ass.net>

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

  parent reply	other threads:[~2020-10-19 15:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-16  6:21 swapon/913 is trying to acquire lock at zcomp_stream_get+0x5/0x90 [zram] but task is already holding lock at zs_map_object+0x7a/0x2e0 Mikhail Gavrilov
2020-10-16 12:40 ` Peter Zijlstra
2020-10-16 14:00   ` Mikhail Gavrilov
2020-10-16 15:33   ` Minchan Kim
2020-10-19 10:13     ` [PATCH] zram: Fix __zram_bvec_{read,write}() locking order Peter Zijlstra
2020-10-19 14:08       ` Minchan Kim
2020-10-19 15:29       ` Sebastian Andrzej Siewior [this message]
2020-10-19 15:32       ` Jens Axboe

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