Re: [PATCH 6/7] fcntl: Don't use ambiguous SIG_POLL si_codes

From: Oleg Nesterov
Date: Thu Jul 20 2017 - 12:16:17 EST


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.