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Date: Thu, 20 Jul 2017 18:16:04 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>, Andrei Vagin <avagin@virtuozzo.com>,
        Thomas Gleixner <tglx@linutronix.de>, Greg KH <greg@kroah.com>,
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        linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
        Linux Containers <containers@lists.linux-foundation.org>,
        Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [PATCH 6/7] fcntl: Don't use ambiguous SIG_POLL si_codes
Message-ID: <20170720161603.GA14430@redhat.com>
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 <20170718140651.15973-6-ebiederm@xmission.com>
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On 07/18, Eric W. Biederman wrote:
>
> -			BUG_ON((reason & __SI_MASK) != __SI_POLL);
> +			BUG_ON((reason < POLL_IN) || (reason > NSIGPOLL));
                                                      ^^^^^^^^^^^^^^^^^
looks obviously wrong? Say, POLL_IN is obviously > NSIGPOLL == 6.

Probably you meant

			BUG_ON((reason < POLL_IN) || (reason - POLL_IN > NSIGPOLL)

?

but this contradicts with the next line:

>  			if (reason - POLL_IN >= NSIGPOLL)
>  				si.si_band  = ~0L;

confused...

Oleg.