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From: Roman Penyaev <rpenyaev@suse.de>
To: "Max Neunhöffer" <max@arangodb.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	Christopher Kohlhoff <chris.kohlhoff@clearpool.io>,
	lars@arangodb.com
Subject: Re: epoll_wait misses edge-triggered eventfd events: bug in Linux 5.3 and 5.4
Date: Tue, 04 Feb 2020 11:35:16 +0100
Message-ID: <d4d188512ea84f243310dd9464922a82@suse.de> (raw)
In-Reply-To: <F0CB2FAC-A6F7-4B72-BC27-413DCF35E256@arangodb.com>

On 2020-02-03 22:03, Max Neunhöffer wrote:
> Hi Roman,
> 
> Thanks for your quick response. This sounds fantastic!
> 
> The epollbug.c program was originally written by my colleague Lars
> Maier and then modified by me and subsequently by Chris Kohlhoff. Note
> that the bugzilla bug report contains altogether three variants which
> test epoll_wait/epoll_ctl in three different ways. It might be
> sensible to take all three variants for the test suite.

I checked 3 variants, they do same things: epoll_ctl() races against
epoll_wait(), and this is exactly the bug reproduction, regardless
actual read() from a file descriptor or EPOLLET flag set.

> I cannot imagine that any of the three authors would object to this, I
> definitely do not, the other two are on Cc in this email and can speak
> for themselves.

I adapted the logic from epollbug.c and included it into 
epoll_wakeup_test.c
test suite, you should have received the email: "[PATCH 3/3] kselftest:
introduce new epoll test case".  Please, take a look or ask your 
colleague
to take a look. If no objections - then fine, leave as is.

Thanks.

--
Roman


      reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-31 13:57 Max Neunhoeffer
2020-02-01 20:16 ` Jakub Kicinski
2020-02-03 15:15   ` Max Neunhoeffer
2020-02-03 16:48     ` Jakub Kicinski
2020-02-03 17:33     ` Roman Penyaev
2020-02-03 21:03       ` Max Neunhöffer
2020-02-04 10:35         ` Roman Penyaev [this message]

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