Date: Fri, 25 Apr 2014 19:16:20 GMT From: Alan Somers <asomers@freebsd.org> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/188997: lock order reversal: (sleepable after non-sleepable) in lacp_attach Message-ID: <201404251916.s3PJGKsv017425@cgiserv.freebsd.org> Resent-Message-ID: <201404251920.s3PJK0uZ056351@freefall.freebsd.org>
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>Number: 188997 >Category: kern >Synopsis: lock order reversal: (sleepable after non-sleepable) in lacp_attach >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Apr 25 19:20:00 UTC 2014 >Closed-Date: >Last-Modified: >Originator: Alan Somers >Release: 11.0 CURRENT >Organization: Spectra Logic >Environment: FreeBSD alans-fbsd-head 11.0-CURRENT FreeBSD 11.0-CURRENT #49 r264887M: Thu Apr 24 17:21:48 MDT 2014 alans@ns1.eng.sldomain.com:/vmpool/obj/usr/home/alans freebsd/head/sys/GENERIC amd64 >Description: r253687 introduced a lock order reversal. It's a lock of a sleepable lock while a nonsleepable lock is still held. The problem is that lacp_attach creates some sysctl nodes, but further up the stack lagg_ioctl called LAGG_WLOCK() on the softc. >How-To-Repeat: ifconfig tap0 create ifconfig tap1 create ifconfig tap2 create ifconfig lagg0 create ifconfig lagg0 up laggproto lacp laggport tap0 laggport tap1 laggport tap2 192.0.0.2/24 >Fix: Two possible solutions come to mind: 1) Move the sysctl node creation out of lacp_attach. Call it from lagg_ioctl after LAGG_WUNLOCK() 2) Turn the sysctl nodes into ioctls instead. That was proposed for a different reason at http://lists.freebsd.org/pipermail/svn-src-head/2013-July/049602.html . >Release-Note: >Audit-Trail: >Unformatted:
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