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From: Christoph Hellwig <hch@infradead.org>
To: Zqiang <qiang.zhang1211@gmail.com>
Cc: akpm@linux-foundation.org, sunhao.th@gmail.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: backing-dev: use kfree_rcu() instead of synchronize_rcu_expedited()
Date: Thu, 14 Oct 2021 13:06:03 +0100	[thread overview]
Message-ID: <YWgdK9OhXa/9N82Y@infradead.org> (raw)
In-Reply-To: <20211014082433.30733-1-qiang.zhang1211@gmail.com>

On Thu, Oct 14, 2021 at 04:24:33PM +0800, Zqiang wrote:
> <IRQ>
>  __init_work+0x2d/0x50
>  synchronize_rcu_expedited+0x3af/0x650
>  bdi_remove_from_list [inline]
>  bdi_unregister+0x17f/0x5c0
>  release_bdi+0xa1/0xc0
>  kref_put [inline]
>  bdi_put+0x72/0xa0
>  bdev_free_inode+0x11e/0x220
>  i_callback+0x3f/0x70
>  rcu_do_batch [inline]
>  rcu_core+0x76d/0x16c0
>  __do_softirq+0x1d7/0x93b
>  invoke_softirq [inline]
>  __irq_exit_rcu [inline]
>  irq_exit_rcu+0xf2/0x130
>  sysvec_apic_timer_interrupt+0x93/0xc0
> 
> The bdi_remove_from_list() is called in RCU softirq, however the
> synchronize_rcu_expedited() will produce sleep action, use kfree_rcu()
> instead of it.

What workload is this running?  If we hit the RCU unregister path
from inode freeing we have a lifetime problem somewhere that we need
to fix first.

      parent reply	other threads:[~2021-10-14 12:08 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-14  8:24 [PATCH] mm: backing-dev: use kfree_rcu() instead of synchronize_rcu_expedited() Zqiang
2021-10-14 11:24 ` Matthew Wilcox
2021-10-15  3:39   ` zhangqiang
     [not found]   ` <CALm+0cUt7iD5zex4-hRv=i1wPd66tz3JYGHz8P8ZFTZcyOCD1A@mail.gmail.com>
     [not found]     ` <d697d61e-27a2-a25c-3ae1-e41457d08705@gmail.com>
2021-10-15 12:35       ` Matthew Wilcox
2021-10-15 13:19         ` Christoph Hellwig
2021-10-18  2:15         ` Zqiang
2021-10-14 12:06 ` Christoph Hellwig [this message]

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