Date: Wed, 8 Mar 2006 21:39:34 -0500 (EST) From: Kris Kennaway <kris@obsecurity.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: bin/94258: O_NONBLOCK may block with rpc.lockd Message-ID: <20060309023934.9141652058@obsecurity.dyndns.org> Resent-Message-ID: <200603090240.k292e8dL084723@freefall.freebsd.org>
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>Number: 94258
>Category: bin
>Synopsis: O_NONBLOCK may block with rpc.lockd
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Thu Mar 09 02:40:07 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator: Kris Kennaway
>Release: FreeBSD 6.0-STABLE i386
>Organization:
FreeBSD
>Environment:
System: FreeBSD xor.obsecurity.org 6.0-STABLE FreeBSD 6.0-STABLE #13: Sun Nov 6 12:45:25 EST 2005 kkenn@xor.obsecurity.org:/mnt/src/sys/i386/compile/XOR i386
>Description:
When the rpc.lockd server is unreachable, locks acquired with
O_NONBLOCK may block. They also block for a few minutes after
rpc.lockd is restarted, but they eventually complete.
>How-To-Repeat:
On the server:
dosirak# killall -KILL rpc.lockd
On the client:
haessal# lockf -t 0 -k pid echo Yay
load: 0.00 cmd: lockf 1467 [lockd] 0.00u 0.00s 0% 528k
[hangs forever]
After rpc.lockd is restarted, it still takes a few minutes for the
lock operation to complete successfully. New locks acquired in this
period also block.
>Fix:
Unsure. Returning EWOULDBLOCK may not be correct since this means
[EWOULDBLOCK] O_NONBLOCK and one of O_SHLOCK or O_EXLOCK is speci-
fied and the file is locked.
and the file may or may not be locked. Perhaps blocking is even
correct behaviour according to the relevant standards, though this is
counter-intuitive.
>Release-Note:
>Audit-Trail:
>Unformatted:
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