Re: kern/45598: expanding uvmexp_sysctl makes top etc fail

[christos%zoulas.com@localhost (Christos Zoulas)]

The following reply was made to PR kern/45598; it has been noted by GNATS.

From: christos%zoulas.com@localhost (Christos Zoulas)
To: gnats-bugs%NetBSD.org@localhost, kern-bug-people%netbsd.org@localhost, 
        gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/45598: expanding uvmexp_sysctl makes top etc fail
Date: Fri, 11 Nov 2011 10:14:16 -0500

 On Nov 11, 10:10am, yamt%NetBSD.org@localhost (yamt%NetBSD.org@localhost) 
wrote:
 -- Subject: kern/45598: expanding uvmexp_sysctl makes top etc fail
 
 |      despite of the comments on the definition of uvmexp_sysctl,
 |      adding new members to the end of the structure actually breaks the abi.
 | 
 |              % top
 |              top: sysctl vm.uvmexp2 failed: Cannot allocate memory
 | 
 |      cf.  http://mail-index.netbsd.org/tech-kern/2005/11/09/0002.html
 | 
 
 Does this fix it?
 
 christos
 
 Index: uvm_meter.c
 ===================================================================
 RCS file: /cvsroot/src/sys/uvm/uvm_meter.c,v
 retrieving revision 1.56
 diff -u -u -r1.56 uvm_meter.c
 --- uvm_meter.c        2 Feb 2011 15:25:27 -0000       1.56
 +++ uvm_meter.c        11 Nov 2011 15:13:47 -0000
 @@ -180,6 +180,8 @@
        node = *rnode;
        node.sysctl_data = &u;
        node.sysctl_size = sizeof(u);
 +      if (oldp)
 +              node.sysctl_size = min(*oldlenp, node.sysctl_size);
        return (sysctl_lookup(SYSCTLFN_CALL(&node)));
  }