NetBSD Problem Report #43452

From www@NetBSD.org  Thu Jun 10 22:13:07 2010
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Date: Thu, 10 Jun 2010 22:13:06 +0000 (UTC)
From: pooka@iki.fi
Reply-To: pooka@iki.fi
To: gnats-bugs@NetBSD.org
Subject: sem_close not possible after sem_unlink
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>Number:         43452
>Category:       kern
>Synopsis:       sem_close not possible after sem_unlink
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    rmind
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 10 22:15:00 +0000 2010
>Closed-Date:    Mon Apr 11 22:36:20 +0000 2011
>Last-Modified:  Fri Mar 09 14:30:02 +0000 2012
>Originator:     Antti Kantee
>Release:        
>Organization:
>Environment:
>Description:
A semaphore for which sem_unlink() is called is supposed to retain
resources until sem_close() is called.  However, sem_close() returns
EINVAL due to sem_unlink() removing evidence of a named semaphore.
>How-To-Repeat:
run tests/lib/semaphore/pthread/t_sem_pth tc unlink:

    unlink: Failed: close unlinked semaphore: Invalid argument

>Fix:

>Release-Note:

>Audit-Trail:
From: Antti Kantee <pooka@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/43452 CVS commit: src/tests/lib/semaphore
Date: Thu, 10 Jun 2010 22:20:38 +0000

 Module Name:	src
 Committed By:	pooka
 Date:		Thu Jun 10 22:20:38 UTC 2010

 Modified Files:
 	src/tests/lib/semaphore: sem.c

 Log Message:
 quote PR kern/43452 in descr


 To generate a diff of this commit:
 cvs rdiff -u -r1.1 -r1.2 src/tests/lib/semaphore/sem.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

Responsible-Changed-From-To: kern-bug-people->rmind
Responsible-Changed-By: rmind@NetBSD.org
Responsible-Changed-When: Sun, 03 Apr 2011 06:40:13 +0000
Responsible-Changed-Why:
Mine!


State-Changed-From-To: open->feedback
State-Changed-By: rmind@NetBSD.org
State-Changed-When: Tue, 05 Apr 2011 11:34:09 +0000
State-Changed-Why:
Code is there, but still deciding whether it is wworth to address the
POSIX spec. requirement.


From: Mindaugas Rasiukevicius <rmind@netbsd.org>
To: gnats-bugs@NetBSD.org
Cc: kern-bug-people@netbsd.org, netbsd-bugs@netbsd.org,
 gnats-admin@netbsd.org, pooka@iki.fi
Subject: Re: kern/43452 (sem_close not possible after sem_unlink)
Date: Tue, 5 Apr 2011 12:31:08 +0100

 > >Number:         43452
 > >Category:       kern
 > >Synopsis:       sem_close not possible after sem_unlink
 > >Confidential:   no
 > >Severity:       non-critical
 > >Priority:       medium
 > >Responsible:    kern-bug-people
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Thu Jun 10 22:15:00 +0000 2010
 > >Originator:     Antti Kantee
 > >Release:        
 > >Organization:
 > >Environment:
 > >Description:
 > A semaphore for which sem_unlink() is called is supposed to retain
 > resources until sem_close() is called.  However, sem_close() returns
 > EINVAL due to sem_unlink() removing evidence of a named semaphore.

 Besides described problem, current semaphore has more issues such as:
 ksem_free() destroying the semaphore before making it invisible;
 ksem_unlink () not checking for permissions; excessive locking (when
 dropping the reference, and heavy RW-lock use), etc.

 Here is basically a rewritten POSIX semaphore - using file descriptor,
 quite more simplified, fixing the bugs:

 http://www.netbsd.org/~rmind/uipc_sem.diff
 http://www.netbsd.org/~rmind/uipc_sem.c 

 However, multiple sem_open(3) calls on the same path return different
 references (file descriptors), which contradicts to POSIX, which has
 unusual requirement here to return the same sem_t address.

 -- 
 Mindaugas

From: "Mindaugas Rasiukevicius" <rmind@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/43452 CVS commit: src/sys
Date: Mon, 11 Apr 2011 22:31:43 +0000

 Module Name:	src
 Committed By:	rmind
 Date:		Mon Apr 11 22:31:43 UTC 2011

 Modified Files:
 	src/sys/kern: uipc_sem.c
 	src/sys/sys: file.h

 Log Message:
 Highly rewrite POSIX semaphore.  Use file descriptor subsystem, greatly
 simplify reference counting, and fix various bugs which existed before,
 e.g. some incorrect locking or mq_unlink() not checking for permissions.

 Also, fixes PR/43452.


 To generate a diff of this commit:
 cvs rdiff -u -r1.29 -r1.30 src/sys/kern/uipc_sem.c
 cvs rdiff -u -r1.71 -r1.72 src/sys/sys/file.h

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: feedback->closed
State-Changed-By: rmind@NetBSD.org
State-Changed-When: Mon, 11 Apr 2011 22:36:20 +0000
State-Changed-Why:
Fixed.


From: "Joerg Sonnenberger" <joerg@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/43452 CVS commit: src/tests/lib/semaphore
Date: Fri, 9 Mar 2012 14:25:35 +0000

 Module Name:	src
 Committed By:	joerg
 Date:		Fri Mar  9 14:25:34 UTC 2012

 Modified Files:
 	src/tests/lib/semaphore: sem.c

 Log Message:
 PR 43452 no longer applies.


 To generate a diff of this commit:
 cvs rdiff -u -r1.9 -r1.10 src/tests/lib/semaphore/sem.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

>Unformatted:

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