linux-next: build warning after merge of the xfs tree

linux-next: build warning after merge of the xfs tree

[Stephen Rothwell]

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Hi Dave,

After merging the xfs tree, today's linux-next build (x86_64 allmodconfig)
produced this warning:

fs/xfs/linux-2.6/xfs_aops.c: In function 'xfs_end_io':
fs/xfs/linux-2.6/xfs_aops.c:232: warning: 'error' may be used uninitialized in this function

Introduced by commit 77d7a0c2eeb285c9069e15396703d0cb9690ac50 ("xfs:
Non-blocking inode locking in IO completion").

I can't tell if this is a false positive.  If the first two "if"
statement bodies are skipped, then error is tested uninitialised.  It is
possible that at least one of them has to be executed.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/

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[PATCH] Re: linux-next: build warning after merge of the xfs tree

[Dave Chinner]

On Thu, Mar 04, 2010 at 11:19:30AM +1100, Stephen Rothwell wrote:
> Hi Dave,
> 
> After merging the xfs tree, today's linux-next build (x86_64 allmodconfig)
> produced this warning:
> 
> fs/xfs/linux-2.6/xfs_aops.c: In function 'xfs_end_io':
> fs/xfs/linux-2.6/xfs_aops.c:232: warning: 'error' may be used uninitialized in this function
> 
> Introduced by commit 77d7a0c2eeb285c9069e15396703d0cb9690ac50 ("xfs:
> Non-blocking inode locking in IO completion").
> 
> I can't tell if this is a false positive.  If the first two "if"
> statement bodies are skipped, then error is tested uninitialised.  It is
> possible that at least one of them has to be executed.

Right, there is a warning being generated there - I thought I fixed
that immediately after posting the first version of the patch. The
second version:

http://oss.sgi.com/archives/xfs/2010-02/msg00340.html

definitely had it fixed.

Alex, can you make sure you take the entire patch rather than
cutting and pasting bits from one patch version to another?  That
way you don't miss small changes to the patch that might have been
forgotten about....

Stephen, the patch below should fix the warning.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

xfs: fix uninitialised variable warning in xfs_end_io

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
 fs/xfs/linux-2.6/xfs_aops.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index f41a2d8..8989c16 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -230,7 +230,7 @@ xfs_end_io(
 {
 	xfs_ioend_t	*ioend = container_of(work, xfs_ioend_t, io_work);
 	struct xfs_inode *ip = XFS_I(ioend->io_inode);
-	int		error;
+	int		error = 0;
 
 	/*
 	 * For unwritten extents we need to issue transactions to convert a

RE: [PATCH] Re: linux-next: build warning after merge of the xfs tree

[Alex Elder]

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> Dave Chinner <mailto:david@fromorbit.com> wrote:
> On Thu, Mar 04, 2010 at 11:19:30AM +1100, Stephen Rothwell wrote:
> > Hi Dave,
> > 
> > After merging the xfs tree, today's linux-next build (x86_64 allmodconfig)
> > produced this warning:
> > 
> > fs/xfs/linux-2.6/xfs_aops.c: In function 'xfs_end_io':
> > fs/xfs/linux-2.6/xfs_aops.c:232: warning: 'error' may be used uninitialized in this function
> > 
> > Introduced by commit 77d7a0c2eeb285c9069e15396703d0cb9690ac50 ("xfs:
> > Non-blocking inode locking in IO completion").
> > 
> > I can't tell if this is a false positive.  If the first two "if"
> > statement bodies are skipped, then error is tested uninitialised.  It is
> > possible that at least one of them has to be executed.
> 
> Right, there is a warning being generated there - I thought I fixed
> that immediately after posting the first version of the patch. The
> second version:
> 
> http://oss.sgi.com/archives/xfs/2010-02/msg00340.html
> 
> definitely had it fixed.
> 
> Alex, can you make sure you take the entire patch rather than
> cutting and pasting bits from one patch version to another?  That
> way you don't miss small changes to the patch that might have been
> forgotten about....

I didn't expect you would change the patch content, only
the description.  I had already tested the previous code
so just grabbed the new description when you re-posted.
Sorry about the warning slipping through.  I'll incorporate
your fix below (tomorrow).

                               -Alex


> Stephen, the patch below should fix the warning.
> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com
> 
> xfs: fix uninitialised variable warning in xfs_end_io
> 
> Signed-off-by: Dave Chinner <david@fromorbit.com>
> ---
>  fs/xfs/linux-2.6/xfs_aops.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
> index f41a2d8..8989c16 100644
> --- a/fs/xfs/linux-2.6/xfs_aops.c
> +++ b/fs/xfs/linux-2.6/xfs_aops.c
> @@ -230,7 +230,7 @@ xfs_end_io(
>  {
>  	xfs_ioend_t	*ioend = container_of(work, xfs_ioend_t, io_work);
>  	struct xfs_inode *ip = XFS_I(ioend->io_inode);
> -	int		error;
> +	int		error = 0;
>  
>  	/*
>  	 * For unwritten extents we need to issue transactions to convert a
> 
> 

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Re: [PATCH] Re: linux-next: build warning after merge of the xfs tree

[Alex Elder]

On Thu, 2010-03-04 at 11:57 +1100, Dave Chinner wrote:
> On Thu, Mar 04, 2010 at 11:19:30AM +1100, Stephen Rothwell wrote:
> > Hi Dave,
> > 
> > After merging the xfs tree, today's linux-next build (x86_64 allmodconfig)
> > produced this warning:
> > 
> > fs/xfs/linux-2.6/xfs_aops.c: In function 'xfs_end_io':
> > fs/xfs/linux-2.6/xfs_aops.c:232: warning: 'error' may be used uninitialized in this function
> > 
> > Introduced by commit 77d7a0c2eeb285c9069e15396703d0cb9690ac50 ("xfs:
> > Non-blocking inode locking in IO completion").
> > 
> > I can't tell if this is a false positive.  If the first two "if"
> > statement bodies are skipped, then error is tested uninitialised.  It is
> > possible that at least one of them has to be executed.
> 
> Right, there is a warning being generated there - I thought I fixed
> that immediately after posting the first version of the patch. The
> second version:
> 
> http://oss.sgi.com/archives/xfs/2010-02/msg00340.html
> 
> definitely had it fixed.
> 
> Alex, can you make sure you take the entire patch rather than
> cutting and pasting bits from one patch version to another?  That
> way you don't miss small changes to the patch that might have been
> forgotten about....

(Sorry if this gets duplicated--I was using a web-based mail
interface yesterday and my first attempt got bounced back
as potential spam.)

I didn't expect you would change the patch content, only
the description.  I had already tested the previous code
so just grabbed the new description when you re-posted.
Sorry about the warning slipping through.  I'll incorporate
your fix soon.
        
                                       -Alex