compiler warnings in 2.6.35.2

compiler warnings in 2.6.35.2

[Chris Frey]

Hi,

When compiling the latest 2.6.35.2 I get a ton of warnings like the
following.  Similar warnings were present in 2.6.35, and I assumed a
stable point release may have tackled them already.  But maybe they
are peculiar to my setup.  Warning below.

- Chris



  CC      mm/swap.o
In file included from include/linux/kobject.h:21,
                 from include/linux/sched.h:91,
                 from mm/swap.c:17:
include/linux/sysfs.h:183: warning: parameter has incomplete type
/home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
/home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints

Re: compiler warnings in 2.6.35.2

[Borislav Petkov]

From: Chris Frey <cdfrey@foursquare.net>
Date: Mon, Aug 16, 2010 at 10:12:52PM -0400

> Hi,
> 
> When compiling the latest 2.6.35.2 I get a ton of warnings like the
> following.  Similar warnings were present in 2.6.35, and I assumed a
> stable point release may have tackled them already.  But maybe they
> are peculiar to my setup.  Warning below.
> 
> - Chris
> 
> 
> 
>   CC      mm/swap.o
> In file included from include/linux/kobject.h:21,
>                  from include/linux/sched.h:91,
>                  from mm/swap.c:17:
> include/linux/sysfs.h:183: warning: parameter has incomplete type
> /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
> /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints

Which compiler version are you using?

-- 
Regards/Gruss,
    Boris.

Re: compiler warnings in 2.6.35.2

[Chris Frey]

On Tue, Aug 17, 2010 at 07:34:56AM +0200, Borislav Petkov wrote:
> From: Chris Frey <cdfrey@foursquare.net>
> Date: Mon, Aug 16, 2010 at 10:12:52PM -0400
> 
> >   CC      mm/swap.o
> > In file included from include/linux/kobject.h:21,
> >                  from include/linux/sched.h:91,
> >                  from mm/swap.c:17:
> > include/linux/sysfs.h:183: warning: parameter has incomplete type
> > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
> > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints
> 
> Which compiler version are you using?

GCC 3.3

- Chris

Re: compiler warnings in 2.6.35.2

[Borislav Petkov]

From: Chris Frey <cdfrey@foursquare.net>
Date: Tue, Aug 17, 2010 at 02:28:01AM -0400

> > >   CC      mm/swap.o
> > > In file included from include/linux/kobject.h:21,
> > >                  from include/linux/sched.h:91,
> > >                  from mm/swap.c:17:
> > > include/linux/sysfs.h:183: warning: parameter has incomplete type
> > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
> > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints
> > 
> > Which compiler version are you using?
> 
> GCC 3.3

Any chance to upgrade to a 4.x version?

-- 
Regards/Gruss,
    Boris.

Re: compiler warnings in 2.6.35.2

[Chris Frey]

On Tue, Aug 17, 2010 at 08:31:59AM +0200, Borislav Petkov wrote:
> From: Chris Frey <cdfrey@foursquare.net>
> Date: Tue, Aug 17, 2010 at 02:28:01AM -0400
> 
> > > >   CC      mm/swap.o
> > > > In file included from include/linux/kobject.h:21,
> > > >                  from include/linux/sched.h:91,
> > > >                  from mm/swap.c:17:
> > > > include/linux/sysfs.h:183: warning: parameter has incomplete type
> > > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
> > > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints
> > > 
> > > Which compiler version are you using?
> > 
> > GCC 3.3
> 
> Any chance to upgrade to a 4.x version?

I could, but Documentation/Changes says gcc 3.2 is the minimum, so I hoped
3.3 would be sufficient.

As for the first warning, doesn't it just need include/linux/kobject.h
to be included for the enum type?

As for the second warning, I'm not sure I even understand it.

- Chris

Re: compiler warnings in 2.6.35.2

[Borislav Petkov]

From: Chris Frey <cdfrey@foursquare.net>
Date: Tue, Aug 17, 2010 at 11:53:33AM -0400

> > > > >   CC      mm/swap.o
> > > > > In file included from include/linux/kobject.h:21,
> > > > >                  from include/linux/sched.h:91,
> > > > >                  from mm/swap.c:17:
> > > > > include/linux/sysfs.h:183: warning: parameter has incomplete type
> > > > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h: In function `__static_cpu_has':
> > > > > /home/cdfrey/kernel/git/linux/arch/x86/include/asm/cpufeature.h:315: warning: asm operand 1 probably doesn't match constraints
> > > > 
> > > > Which compiler version are you using?
> > > 
> > > GCC 3.3
> > 
> > Any chance to upgrade to a 4.x version?
> 
> I could, but Documentation/Changes says gcc 3.2 is the minimum, so I hoped
> 3.3 would be sufficient.

This is actually something we're looking to change now:
http://lkml.indiana.edu/hypermail/linux/kernel/1005.2/01239.html

@hpa: there are some gcc3.x users left, obviously.

> 
> As for the first warning, doesn't it just need include/linux/kobject.h
> to be included for the enum type?

This is a gcc 3.x problem AFAIK.

> As for the second warning, I'm not sure I even understand it.

Ditto.

So why do you want to stay with 3.x anyway?

-- 
Regards/Gruss,
Boris.

Re: compiler warnings in 2.6.35.2

[Anca Emanuel]

On Tue, Aug 17, 2010 at 7:20 PM, Borislav Petkov <bp@alien8.de> wrote:
> So why do you want to stay with 3.x anyway?

Read this: http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/BUILD.LOG
Search for warnings.
I tried to complile myself (using ubuntu 10.10 with latest updates),
but failed at some staging driver. After uncheked the staging drivers,
still failure.
I'm using kernel 2.6.36-rc1 from
http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/

Re: compiler warnings in 2.6.35.2

[Borislav Petkov]

From: Anca Emanuel <anca.emanuel@gmail.com>
Date: Tue, Aug 17, 2010 at 08:15:21PM +0300

> On Tue, Aug 17, 2010 at 7:20 PM, Borislav Petkov <bp@alien8.de> wrote:
> > So why do you want to stay with 3.x anyway?
> 
> Read this: http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/BUILD.LOG
> Search for warnings.
> I tried to complile myself (using ubuntu 10.10 with latest updates),
> but failed at some staging driver. After uncheked the staging drivers,
> still failure.
> I'm using kernel 2.6.36-rc1 from
> http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/

Can you please elaborate a bit more, what are you trying to show here?

-- 
Regards/Gruss,
    Boris.

Re: compiler warnings in 2.6.35.2

[Anca Emanuel]

On Tue, Aug 17, 2010 at 9:45 PM, Borislav Petkov <bp@alien8.de> wrote:
> From: Anca Emanuel <anca.emanuel@gmail.com>
> Date: Tue, Aug 17, 2010 at 08:15:21PM +0300
>
>> On Tue, Aug 17, 2010 at 7:20 PM, Borislav Petkov <bp@alien8.de> wrote:
>> > So why do you want to stay with 3.x anyway?
>>
>> Read this: http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/BUILD.LOG
>> Search for warnings.
>> I tried to complile myself (using ubuntu 10.10 with latest updates),
>> but failed at some staging driver. After uncheked the staging drivers,
>> still failure.
>> I'm using kernel 2.6.36-rc1 from
>> http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-rc1-maverick/
>
> Can you please elaborate a bit more, what are you trying to show here?
>
> --
> Regards/Gruss,
>    Boris.
>

Steps to reproduce:
1. Install Ubuntu 10.04, and upgrade to 10.10
2. Use this tutorial to compile the kernel:
https://wiki.ubuntu.com/KernelTeam/GitKernelBuild

There is a lot of compiler warnings, and this problem is not new.
I think that is enough for this moment.

( If you can boot from it please show how did you do it )

Re: compiler warnings in 2.6.35.2

[Greg KH]

[-- Attachment #1: Type: text/plain, Size: 696 bytes --]

On Mon, Aug 16, 2010 at 10:12:52PM -0400, Chris Frey wrote:
> Hi,
> 
> When compiling the latest 2.6.35.2 I get a ton of warnings like the
> following.  Similar warnings were present in 2.6.35, and I assumed a
> stable point release may have tackled them already.  But maybe they
> are peculiar to my setup.  Warning below.
> 
> - Chris
> 
> 
> 
>   CC      mm/swap.o
> In file included from include/linux/kobject.h:21,
>                  from include/linux/sched.h:91,
>                  from mm/swap.c:17:
> include/linux/sysfs.h:183: warning: parameter has incomplete type

Known issue, will show up in a future .35.y kernel release.  The patch
is below if you need it now.

thanks,

greg k-h

[-- Attachment #2: kobject-break-the-kobject-namespace-defs-into-their-own-header.patch --]
[-- Type: text/x-patch, Size: 4767 bytes --]

>From dhowells@redhat.com  Thu Aug 12 13:40:21 2010
From: David Howells <dhowells@redhat.com>
Subject: kobject: Break the kobject namespace defs into their own header
To: ebiederm@xmission.com, gregkh@suse.de
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	David Howells <dhowells@redhat.com>
Date: Wed, 11 Aug 2010 15:01:02 +0100
Message-ID: <20100811140102.19596.84876.stgit@warthog.procyon.org.uk>

Break the kobject namespace defs into their own header to avoid a header file
inclusion ordering problem between linux/sysfs.h and linux/kobject.h.

This fixes the build breakage on older versions of gcc.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 include/linux/kobject.h    |   35 ----------------------------
 include/linux/kobject_ns.h |   56 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/sysfs.h      |    1 
 3 files changed, 58 insertions(+), 34 deletions(-)

--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -22,6 +22,7 @@
 #include <linux/compiler.h>
 #include <linux/spinlock.h>
 #include <linux/kref.h>
+#include <linux/kobject_ns.h>
 #include <linux/kernel.h>
 #include <linux/wait.h>
 #include <asm/atomic.h>
@@ -136,42 +137,8 @@ struct kobj_attribute {
 
 extern const struct sysfs_ops kobj_sysfs_ops;
 
-/*
- * Namespace types which are used to tag kobjects and sysfs entries.
- * Network namespace will likely be the first.
- */
-enum kobj_ns_type {
-	KOBJ_NS_TYPE_NONE = 0,
-	KOBJ_NS_TYPE_NET,
-	KOBJ_NS_TYPES
-};
-
 struct sock;
 
-/*
- * Callbacks so sysfs can determine namespaces
- *   @current_ns: return calling task's namespace
- *   @netlink_ns: return namespace to which a sock belongs (right?)
- *   @initial_ns: return the initial namespace (i.e. init_net_ns)
- */
-struct kobj_ns_type_operations {
-	enum kobj_ns_type type;
-	const void *(*current_ns)(void);
-	const void *(*netlink_ns)(struct sock *sk);
-	const void *(*initial_ns)(void);
-};
-
-int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
-int kobj_ns_type_registered(enum kobj_ns_type type);
-const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
-const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
-
-const void *kobj_ns_current(enum kobj_ns_type type);
-const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
-const void *kobj_ns_initial(enum kobj_ns_type type);
-void kobj_ns_exit(enum kobj_ns_type type, const void *ns);
-
-
 /**
  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
  *
--- /dev/null
+++ b/include/linux/kobject_ns.h
@@ -0,0 +1,56 @@
+/* Kernel object name space definitions
+ *
+ * Copyright (c) 2002-2003 Patrick Mochel
+ * Copyright (c) 2002-2003 Open Source Development Labs
+ * Copyright (c) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (c) 2006-2008 Novell Inc.
+ *
+ * Split from kobject.h by David Howells (dhowells@redhat.com)
+ *
+ * This file is released under the GPLv2.
+ *
+ * Please read Documentation/kobject.txt before using the kobject
+ * interface, ESPECIALLY the parts about reference counts and object
+ * destructors.
+ */
+
+#ifndef _LINUX_KOBJECT_NS_H
+#define _LINUX_KOBJECT_NS_H
+
+struct sock;
+struct kobject;
+
+/*
+ * Namespace types which are used to tag kobjects and sysfs entries.
+ * Network namespace will likely be the first.
+ */
+enum kobj_ns_type {
+	KOBJ_NS_TYPE_NONE = 0,
+	KOBJ_NS_TYPE_NET,
+	KOBJ_NS_TYPES
+};
+
+/*
+ * Callbacks so sysfs can determine namespaces
+ *   @current_ns: return calling task's namespace
+ *   @netlink_ns: return namespace to which a sock belongs (right?)
+ *   @initial_ns: return the initial namespace (i.e. init_net_ns)
+ */
+struct kobj_ns_type_operations {
+	enum kobj_ns_type type;
+	const void *(*current_ns)(void);
+	const void *(*netlink_ns)(struct sock *sk);
+	const void *(*initial_ns)(void);
+};
+
+int kobj_ns_type_register(const struct kobj_ns_type_operations *ops);
+int kobj_ns_type_registered(enum kobj_ns_type type);
+const struct kobj_ns_type_operations *kobj_child_ns_ops(struct kobject *parent);
+const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
+
+const void *kobj_ns_current(enum kobj_ns_type type);
+const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
+const void *kobj_ns_initial(enum kobj_ns_type type);
+void kobj_ns_exit(enum kobj_ns_type type, const void *ns);
+
+#endif /* _LINUX_KOBJECT_NS_H */
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -16,6 +16,7 @@
 #include <linux/errno.h>
 #include <linux/list.h>
 #include <linux/lockdep.h>
+#include <linux/kobject_ns.h>
 #include <asm/atomic.h>
 
 struct kobject;