From: Jens Axboe <jaxboe@fusionio.com>
To: Tejun Heo <tj@kernel.org>
Cc: Dave Jones <davej@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Sasha Levin <levinsasha928@gmail.com>
Subject: Re: [PATCH v3.4-rc5] block: iocontext->nr_tasks should be initialized to one
Date: Tue, 1 May 2012 20:02:39 +0200 [thread overview]
Message-ID: <4FA0253F.4000302@fusionio.com> (raw)
In-Reply-To: <20120501161729.GV26595@google.com>
On 2012-05-01 18:17, Tejun Heo wrote:
> create_task_io_context() left ioc->nr_tasks at zero; however, a newly
> created ioc should have its nr_tasks initialized to one as it begins
> attached to the task creating it.
>
> This affects only CLONE_IO which currently doesn't seem to have any
> actual user. Sasha triggered WARN_ON_ONCE() in ioc_task_link() using
> syscall fuzzer. Even when it happens, the failure mode isn't critical
> (blk-cgroup may allow attaching a CLONE_IO'd task to a cgroup when it
> shouldn't and blkcg limits may behave weirdly).
CLONE_IO is an exported interface, it can be set from clone(2).
Otherwise Sasha would not have hit this :-)
Thanks, applied.
--
Jens Axboe
next prev parent reply other threads:[~2012-05-01 18:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-01 12:05 WARNING: at include/linux/iocontext.h:140 copy_io+0xb9/0x130() Sasha Levin
2012-05-01 16:17 ` [PATCH v3.4-rc5] block: iocontext->nr_tasks should be initialized to one Tejun Heo
2012-05-01 18:02 ` Jens Axboe [this message]
2012-05-01 18:09 ` Tejun Heo
2012-05-01 18:18 ` Jens Axboe
2012-05-01 18:31 ` Jeff Moyer
2012-05-01 18:36 ` Vivek Goyal
2012-05-01 18:48 ` Jeff Moyer
2012-05-01 18:59 ` Vivek Goyal
2012-05-01 19:04 ` Jeff Moyer
2012-05-01 19:08 ` Vivek Goyal
2012-05-01 18:37 ` Jens Axboe
2012-05-01 18:50 ` Jeff Moyer
2012-05-01 19:03 ` Jens Axboe
2012-05-01 18:04 ` Jens Axboe
2012-05-01 18:06 ` Tejun Heo
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