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Date: Mon, 09 Dec 2002 14:39:06 +0300
From: Vladimir B.Grebenschikov <vova@sw.r>
Sender: "Vladimir B. Grebenschikov" <vova@sw.ru>
Reply-To: Vladimir B.Grebenschikov <vova@sw.ru>
To: FreeBSD-gnats-submit@freebsd.org
Cc:
Subject: msgget() can return negative value after extensive use
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>Number:         46122
>Category:       kern
>Synopsis:       msgget() can return negative value after extensive use
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    maxim
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Dec 09 03:40:04 PST 2002
>Closed-Date:    Tue Dec 31 00:57:30 PST 2002
>Last-Modified:  Tue Dec 31 00:57:30 PST 2002
>Originator:     Vladimir B. Grebenschikov
>Release:        FreeBSD 5.0-RC i386
>Organization:
SWsoft
>Environment:
System: FreeBSD vbook.express.ru 5.0-RC FreeBSD 5.0-RC #23: Sun Dec 8 14:54:44 MSK 2002 root@vbook.express.ru:/usr/local/src/sys/i386/compile/VBOOK i386

This bug also appears in 4-STABLE branch

>Description:

msgget() function according to manpage should return positive identifier,
but after some hours of extencive use kernel counter overflowed and negative
number is returned.

>How-To-Repeat:

I have use perl test suite.
perl lib/IPC/SysV.t

>Fix:

Below kernel patch to fix problem

Index: kern/sysv_msg.c
===================================================================
RCS file: /ext/vcvs/src/sys/kern/sysv_msg.c,v
retrieving revision 1.23.2.3.10000.7
diff -u -r1.23.2.3.10000.7 sysv_msg.c
--- kern/sysv_msg.c	2 Dec 2002 16:44:36 -0000	1.23.2.3.10000.7
+++ kern/sysv_msg.c	9 Dec 2002 10:24:45 -0000
@@ -440,7 +440,7 @@
 		msqptr->msg_perm.gid = cred->cr_gid;
 		msqptr->msg_perm.mode = (msgflg & 0777);
 		/* Make sure that the returned msqid is unique */
-		msqptr->msg_perm.seq++;
+		msqptr->msg_perm.seq = (msqptr->msg_perm.seq+1) & 0x7fff;
 		msqptr->msg_first = NULL;
 		msqptr->msg_last = NULL;
 		msqptr->msg_cbytes = 0;


>Release-Note:
>Audit-Trail:
State-Changed-From-To: open->patched 
State-Changed-By: maxim 
State-Changed-When: Sun Dec 15 02:00:13 PST 2002 
State-Changed-Why:  
Fixed in rev. 1.44 src/sys/kern/sysv_msg.c. Thanks! 


Responsible-Changed-From-To: freebsd-bugs->maxim 
Responsible-Changed-By: maxim 
Responsible-Changed-When: Sun Dec 15 02:00:13 PST 2002 
Responsible-Changed-Why:  
Will MFC the fix in two weeks. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=46122 
State-Changed-From-To: patched->closed 
State-Changed-By: maxim 
State-Changed-When: Tue Dec 31 00:56:32 PST 2002 
State-Changed-Why:  
Fixed in rev. 1.44 and rev. 1.23.2.5 src/sys/kern/sysv_msg.c in -CURRENT 
and -STABLE. Thanks! 

http://www.freebsd.org/cgi/query-pr.cgi?pr=46122 
>Unformatted:
