From: Wu Fengguang <fengguang.wu@intel.com>
To: Rabin Vincent <rabin@rab.in>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org, chanho0207@gmail.com
Subject: Re: [PATCHv2] backing-dev: fix wakeup timer races with bdi_unregister()
Date: Tue, 31 Jan 2012 21:24:03 +0800 [thread overview]
Message-ID: <20120131132403.GA20016@localhost> (raw)
In-Reply-To: <1326991820-31393-1-git-send-email-rabin@rab.in>
On Thu, Jan 19, 2012 at 10:20:20PM +0530, Rabin Vincent wrote:
> While 7a401a972df8e18 ("backing-dev: ensure wakeup_timer is deleted")
> addressed the problem of the bdi being freed with a queued wakeup
> timer, there are other races that could happen if the wakeup timer
> expires after/during bdi_unregister(), before bdi_destroy() is called.
>
> wakeup_timer_fn() could attempt to wakeup a task which has already has
> been freed, or could access a NULL bdi->dev via the wake_forker_thread
> tracepoint.
>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: Wu Fengguang <fengguang.wu@intel.com>
> Reported-by: Chanho Min <chanho.min@lge.com>
> Signed-off-by: Rabin Vincent <rabin@rab.in>
> ---
Thanks. I just pushed it to linux-next, together with this related one:
Subject: writeback: fix NULL bdi->dev in trace writeback_single_inode
Date: Tue Jan 17 11:18:56 CST 2012
bdi_prune_sb() resets sb->s_bdi to default_backing_dev_info when the
tearing down the original bdi. Fix trace_writeback_single_inode to
use sb->s_bdi=default_backing_dev_info rather than bdi->dev=NULL for a
teared down bdi.
Reported-by: Rabin Vincent <rabin@rab.in>
Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Thanks,
Fengguang
prev parent reply other threads:[~2012-01-31 13:34 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 8:49 [PATCH] mm/backing-dev.c: fix crash when USB/SCSI device is detached Chanho Min
2012-01-15 10:28 ` Rabin Vincent
2012-01-15 12:58 ` Wu Fengguang
2012-01-15 15:41 ` Rabin Vincent
2012-01-16 2:53 ` Wu Fengguang
2012-01-16 5:28 ` Chanho Min
2012-01-16 5:50 ` Wu Fengguang
2012-01-16 5:53 ` Wu Fengguang
2012-01-16 6:34 ` Chanho Min
2012-01-18 19:43 ` Rabin Vincent
2012-01-19 16:50 ` [PATCHv2] backing-dev: fix wakeup timer races with bdi_unregister() Rabin Vincent
2012-01-19 23:46 ` Namjae Jeon
2012-01-20 5:24 ` Rabin Vincent
2012-01-20 6:15 ` Namjae Jeon
2012-01-20 10:03 ` Rabin Vincent
2012-01-20 11:18 ` Namjae Jeon
2012-01-20 12:08 ` Rabin Vincent
2012-01-20 15:04 ` Namjae Jeon
2012-01-31 13:24 ` Wu Fengguang [this message]
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