diff mbox

btrfs: fix uninitialized variable warning

Message ID 20110603145014.GU12709@twin.jikos.cz (mailing list archive)
State New, archived
Headers show

Commit Message

David Sterba June 3, 2011, 2:50 p.m. UTC 
From: David Sterba <dsterba@suse.cz>

With Linus' tree, today's linux-next build (powercp ppc64_defconfig)
produced this warning:

fs/btrfs/delayed-inode.c: In function 'btrfs_delayed_update_inode':
fs/btrfs/delayed-inode.c:1598:6: warning: 'ret' may be used
uninitialized in this function

Introduced by commit 16cdcec736cd ("btrfs: implement delayed inode items
operation").

This fixes a bug in btrfs_update_inode(): if the returned value from
btrfs_delayed_update_inode is a nonzero garbage, inode stat data are not
updated and several call paths may hit a BUG_ON or fail with strange
code.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David Sterba <dsterba@suse.cz>
---

patch pushed to git://repo.or.cz/linux-2.6/btrfs-unstable.git #fixes

 fs/btrfs/delayed-inode.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

Comments

Chris Mason June 3, 2011, 2:56 p.m. UTC | #1 
Excerpts from David Sterba's message of 2011-06-03 10:50:14 -0400:
> From: David Sterba <dsterba@suse.cz>
> 
> With Linus' tree, today's linux-next build (powercp ppc64_defconfig)
> produced this warning:
> 
> fs/btrfs/delayed-inode.c: In function 'btrfs_delayed_update_inode':
> fs/btrfs/delayed-inode.c:1598:6: warning: 'ret' may be used
> uninitialized in this function
> 
> Introduced by commit 16cdcec736cd ("btrfs: implement delayed inode items
> operation").
> 
> This fixes a bug in btrfs_update_inode(): if the returned value from
> btrfs_delayed_update_inode is a nonzero garbage, inode stat data are not
> updated and several call paths may hit a BUG_ON or fail with strange
> code.

Ugh, thanks!  It looks like the gcc uninit stuff isn't as verbose as it
used to be, but it does catch a bunch of allocated/set but not used
vars.

I have a nitems = 0 fix in my tree as well.

-chris
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diff mbox

Patch

diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index 01e2950..8cb012f 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -1595,7 +1595,7 @@  int btrfs_delayed_update_inode(struct btrfs_trans_handle *trans,
 			       struct btrfs_root *root, struct inode *inode)
 {
 	struct btrfs_delayed_node *delayed_node;
-	int ret;
+	int ret = 0;
 
 	delayed_node = btrfs_get_or_create_delayed_node(inode);
 	if (IS_ERR(delayed_node))