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Date: Mon, 16 Jan 2012 15:34:09 +0900
Message-ID: <CAOAMb1B7oENhPzgUkFjzuJ0==dnHRJkmHFSq-7QtSGeV6JeBvA@mail.gmail.com>
Subject: Re: [PATCH] mm/backing-dev.c: fix crash when USB/SCSI device is detached
From: Chanho Min <chanho0207@gmail.com>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Rabin Vincent <rabin@rab.in>, Jens Axboe <axboe@kernel.dk>,
        linux-kernel@vger.kernel.org
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> But wait.. Rabin's patch actually fixes the NULL deference in
> the call
>
>        trace_writeback_wake_forker_thread(bdi);
>
> The wakeup of the forker thread should be harmless.
>
The forker thread shoud not be woken up after the bdi is unregistered.
Is this also Rabin's intention?
Also, I'm not sure the wakeup of the forker thread is harmless as bellows.
..
case FORK_THREAD:
..
  task = kthread_create(bdi_writeback_thread, &bdi->wb,
		      "flush-%s", dev_name(bdi->dev));

Thanks
Chanho