Date: Thu, 21 May 2009 16:30:08 GMT From: John Baldwin <jhb@freebsd.org> To: freebsd-amd64@FreeBSD.org Subject: Re: amd64/134786: [patch] vfs.bufspace sysctl wideness on amd64 Message-ID: <200905211630.n4LGU82W040594@freefall.freebsd.org>
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The following reply was made to PR amd64/134786; it has been noted by GNATS. From: John Baldwin <jhb@freebsd.org> To: freebsd-amd64@freebsd.org Cc: Emil Mikulic <emikulic@gmail.com>, FreeBSD-gnats-submit@freebsd.org Subject: Re: amd64/134786: [patch] vfs.bufspace sysctl wideness on amd64 Date: Thu, 21 May 2009 12:16:26 -0400 On Thursday 21 May 2009 10:48:25 am Emil Mikulic wrote: > > >Number: 134786 > >Category: amd64 > >Synopsis: [patch] vfs.bufspace sysctl wideness on amd64 > >Confidential: no > >Severity: non-critical > >Priority: low > >Responsible: freebsd-amd64 > >State: open > >Quarter: > >Keywords: > >Date-Required: > >Class: sw-bug > >Submitter-Id: current-users > >Arrival-Date: Thu May 21 14:50:04 UTC 2009 > >Closed-Date: > >Last-Modified: > >Originator: Emil Mikulic > >Release: FreeBSD 8-CURRENT > >Organization: > >Environment: > >Description: > > On amd64, providing a 64-bit buffer to get the vfs.bufspace sysctl will > return a 64-bit (long) quantity, but providing a *larger* buffer will > only yield a 32-bit (int) quantity. > > >How-To-Repeat: > > len = 8; > sysctlbyname("vfs.bufspace", &buf, &len, NULL, 0); > /* len is still 8 */ > > len = 10; > sysctlbyname("vfs.bufspace", &buf, &len, NULL, 0); > /* len is 4! */ > > >Fix: > > --- sys/kern/vfs_bio.c 2009-04-17 10:01:39.000000000 +0000 > +++ sys/kern/vfs_bio.c.2 2009-05-09 09:27:16.000000000 +0000 > @@ -288,15 +288,15 @@ > defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7) > static int > sysctl_bufspace(SYSCTL_HANDLER_ARGS) > { > long lvalue; > int ivalue; > > - if (sizeof(int) == sizeof(long) || req->oldlen == sizeof(long)) > + if (sizeof(int) == sizeof(long) || req->oldlen >= sizeof(long)) > return (sysctl_handle_long(oidp, arg1, arg2, req)); > lvalue = *(long *)arg1; > if (lvalue > INT_MAX) > /* On overflow, still write out a long to trigger ENOMEM. */ > return (sysctl_handle_long(oidp, &lvalue, 0, req)); > ivalue = lvalue; > return (sysctl_handle_int(oidp, &ivalue, 0, req)); Hummm. I guess that is correct, though that is a bit odd. -- John Baldwin
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