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From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>, io-uring@vger.kernel.org
Subject: Re: [PATCH v2] io_uring: fix dead-hung for non-iter fixed rw
Date: Sun, 24 Nov 2019 10:10:25 -0700	[thread overview]
Message-ID: <6a2fcf67-1267-a02a-98ce-435bbb2ca9bb@kernel.dk> (raw)
In-Reply-To: <620023b272fef0fd76d0f91ff1876fa64864caa6.1574585281.git.asml.silence@gmail.com>

On 11/24/19 1:58 AM, Pavel Begunkov wrote:
> Read/write requests to devices without implemented read/write_iter
> using fixed buffers causes general protection fault, which totally
> hangs a machine.
> 
> io_import_fixed() initialises iov_iter with bvec, but loop_rw_iter()
> accesses it as iovec, so dereferencing random address.
> 
> kmap() page by page in this case

This looks good to me, much cleaner/simpler. I've added a few pipe fixed
buffer tests to liburing as well. Didn't crash for me, but obvious
garbage coming out. I've flagged this for stable as well.

-- 
Jens Axboe


  reply	other threads:[~2019-11-24 17:10 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1574585281.git.asml.silence@gmail.com>
2019-11-24  8:58 ` [PATCH v2] io_uring: fix dead-hung for non-iter fixed rw Pavel Begunkov
2019-11-24 17:10   ` Jens Axboe [this message]
2019-11-24 17:52     ` Pavel Begunkov
2019-11-25  0:43       ` Jackie Liu
2019-11-25  2:38         ` Jens Axboe
2019-11-25  3:33           ` Jackie Liu
2019-11-25  3:47             ` Jens Axboe
2019-11-25 10:12             ` Pavel Begunkov
2019-11-25  2:37       ` Jens Axboe
2019-11-25 10:46         ` Pavel Begunkov

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