linux-kernel - Re: [PATCH 5.0 047/246] fs: Make splice() and tee() take into account O

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Message-ID: <20190406142036.GD2935@sasha-vm>
Date:   Sat, 6 Apr 2019 10:20:36 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
Cc:     Slavomir Kaslev <kaslevs@...are.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "rostedt@...dmis.org" <rostedt@...dmis.org>
Subject: Re: [PATCH 5.0 047/246] fs: Make splice() and tee() take into
 account O_NONBLOCK flag on pipes

On Thu, Apr 04, 2019 at 07:32:00PM +0200, gregkh@...uxfoundation.org wrote:
>On Thu, Apr 04, 2019 at 04:16:57PM +0000, Slavomir Kaslev wrote:
>> On Thu, 2019-04-04 at 10:45 +0200, Greg Kroah-Hartman wrote:
>> > 5.0-stable review patch.  If anyone has any objections, please let me
>> > know.
>> >
>> > ------------------
>> >
>> > [ Upstream commit ee5e001196d1345b8fee25925ff5f1d67936081e ]
>> >
>> > The current implementation of splice() and tee() ignores O_NONBLOCK
>> > set
>> > on pipe file descriptors and checks only the SPLICE_F_NONBLOCK flag
>> > for
>> > blocking on pipe arguments.  This is inconsistent since splice()-ing
>> > from/to non-pipe file descriptors does take O_NONBLOCK into
>> > consideration.
>> >
>> > Fix this by promoting O_NONBLOCK, when set on a pipe, to
>> > SPLICE_F_NONBLOCK.
>>
>> [...]
>>
>> > This change does have potential of breaking users who don't expect
>> > EAGAIN from splice() when SPLICE_F_NONBLOCK is not set.  OTOH
>> > programs
>> > that set O_NONBLOCK and don't anticipate EAGAIN are arguably
>> > buggy[2].
>>
>> Hi Greg,
>>
>> Can you drop this one from the stable queues? We discussed it with
>> Sasha[1] already in the autosel patches thread.
>>
>> [1] https://lkml.org/lkml/2019/4/3/811
>
>Dropped from everywhere now.
>
>Sasha, how did this still get in?

Sorry about that, I dropped it from the wrong local branch :(

--
Thanks,
Sasha