[PATCH] x86: Get rid of 'dubious one-bit signed bitfield' sprase warning

[PATCH] x86: Get rid of 'dubious one-bit signed bitfield' sprase warning

[Anton Vorontsov]

This very noisy sparse warning appears on almost every file in the
kernel:

  CHECK   init/main.c
arch/x86/include/asm/thread_info.h:43:55: error: dubious one-bit signed bitfield
arch/x86/include/asm/thread_info.h:44:46: error: dubious one-bit signed bitfield

This patch changes sig_on_uaccess_error and uaccess_err flags to unsigned
type and thus fixes the warning.

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
---

Not sure why this warning is still there, as it spams the build process
a lot. I googled some discussion dated month ago... but no one sent a
patch?

http://www.spinics.net/lists/linux-kernel-janitors/msg10172.html

I went safest way, i.e. changing types to unsigned instead of bool/__u8.

 arch/x86/include/asm/thread_info.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 7404715..bc817cd 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -40,8 +40,8 @@ struct thread_info {
 						*/
 	__u8			supervisor_stack[0];
 #endif
-	int			sig_on_uaccess_error:1;
-	int			uaccess_err:1;	/* uaccess failed */
+	unsigned int		sig_on_uaccess_error:1;
+	unsigned int		uaccess_err:1;	/* uaccess failed */
 };
 
 #define INIT_THREAD_INFO(tsk)			\
-- 
1.7.7.3

Re: [PATCH] x86: Get rid of 'dubious one-bit signed bitfield' sprase warning

[Andy Lutomirski]

On Tue, Jan 10, 2012 at 5:11 PM, Anton Vorontsov <cbouatmailru@gmail.com> wrote:
> This very noisy sparse warning appears on almost every file in the
> kernel:
>
>  CHECK   init/main.c
> arch/x86/include/asm/thread_info.h:43:55: error: dubious one-bit signed bitfield
> arch/x86/include/asm/thread_info.h:44:46: error: dubious one-bit signed bitfield
>
> This patch changes sig_on_uaccess_error and uaccess_err flags to unsigned
> type and thus fixes the warning.
>
> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
> ---

Acked-by: Andy Lutomirski <luto@mit.edu>

This structure isn't used by userspace (or not usefully, anyway --
it's not at all stable across releases).

--Andy

[tip:x86/urgent] x86: Get rid of dubious one-bit signed bitfield

[tip-bot for Anton Vorontsov]

Commit-ID:  f10448689d95b9516c656ccd4078839e656656e7
Gitweb:     http://git.kernel.org/tip/f10448689d95b9516c656ccd4078839e656656e7
Author:     Anton Vorontsov <cbouatmailru@gmail.com>
AuthorDate: Wed, 11 Jan 2012 05:11:46 +0400
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Mon, 16 Jan 2012 09:39:54 +0100

x86: Get rid of dubious one-bit signed bitfield

This very noisy sparse warning appears on almost every file in
the kernel:

  CHECK   init/main.c
  arch/x86/include/asm/thread_info.h:43:55: error: dubious one-bit
  signed bitfield arch/x86/include/asm/thread_info.h:44:46: error:
  dubious one-bit signed bitfield

Sparse is right and this patch changes sig_on_uaccess_error and
uaccess_err flags to unsigned type and thus fixes the warning.

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Acked-by: Andy Lutomirski <luto@mit.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Dan Carpenter <error27@gmail.com>
Link: http://lkml.kernel.org/r/20120111011146.GA30428@oksana.dev.rtsoft.ru
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/include/asm/thread_info.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 185b719..56a63ff 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -40,8 +40,8 @@ struct thread_info {
 						*/
 	__u8			supervisor_stack[0];
 #endif
-	int			sig_on_uaccess_error:1;
-	int			uaccess_err:1;	/* uaccess failed */
+	unsigned int		sig_on_uaccess_error:1;
+	unsigned int		uaccess_err:1;	/* uaccess failed */
 };
 
 #define INIT_THREAD_INFO(tsk)			\