linux-kernel - looking for explanation of select() timeout behaviour

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <485FC89A.30309@nortel.com>
Date:	Mon, 23 Jun 2008 10:00:26 -0600
From:	"Chris Friesen" <cfriesen@...tel.com>
To:	netdev@...r.kernel.org
CC:	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: looking for explanation of select() timeout behaviour

I've got something odd in a recent strace log (running on an older 
kernel, I haven't yet tried to reproduce in mainline):

20418 22:06:50.583303 select(19, [7 11 12 13 14 15 16 17 18], NULL, 
NULL, {0, 498508}) = 1 (in [11], left {0, 0}) <5.074137>

select() was called with a timeout of half a second.  Five seconds later 
it returns with zero time left and a single socket readable.  Why 
wouldn't it have returned after half a second with a timeout?

My immediate suspicion would be to look at scheduler behaviour, but are 
there any other explanations?  I'm fairly sure system time wasn't 
changed during this interval (the system should have been ntp-synced).

Thanks,

Chris
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/