linux-kernel - [PATCH] sysfs: kill an extra put in sysfs_create

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Message-ID: <20070718071445.GI23568@htj.dyndns.org>
Date:	Wed, 18 Jul 2007 16:14:45 +0900
From:	Tejun Heo <htejun@...il.com>
To:	Gabriel C <nix.or.die@...glemail.com>
Cc:	Satyam Sharma <satyam.sharma@...il.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Christoph Lameter <clameter@....com>, gregkh@...e.de,
	miles.lane@...il.com
Subject: [PATCH] sysfs: kill an extra put in sysfs_create_link() failure path

There is a subtle bug in sysfs_create_link() failure path.  When
symlink creation fails because there's already a node with the same
name, the target sysfs_dirent is put twice - once by failure path of
sysfs_create_link() and once more when the symlink is released.

Fix it by making only the symlink node responsible for putting
target_sd.

Signed-off-by: Tejun Heo <htejun@...il.com>
---
Gabriel, Miles, please verify this fixes your problem.  Thanks.

 fs/sysfs/symlink.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index 2f86e04..d056e96 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -86,7 +86,9 @@ int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char
 	sd = sysfs_new_dirent(name, S_IFLNK|S_IRWXUGO, SYSFS_KOBJ_LINK);
 	if (!sd)
 		goto out_put;
+
 	sd->s_elem.symlink.target_sd = target_sd;
+	target_sd = NULL;	/* reference is now owned by the symlink */
 
 	sysfs_addrm_start(&acxt, parent_sd);
 
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
-
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