[PATCH 2.6.24-rc7 1/2] sysfs: make sysfs_lookup() return ERR_PTR(-ENOENT)on failed lookup

From: Tejun Heo
Date: Tue Jan 15 2008 - 22:06:30 EST


sysfs tries to keep dcache a strict subset of sysfs_dirent tree by
shooting down dentries when a node is removed, that is, no negative
dentry for sysfs. However, the lookup function returned NULL and thus
created negative dentries when the target node didn't exist.

Make sysfs_lookup() return ERR_PTR(-ENOENT) on lookup failure. This
fixes the NULL dereference bug in sysfs_get_dentry() discovered by
bluetooth rfcomm device moving around.

Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
fs/sysfs/dir.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

Index: work/fs/sysfs/dir.c
===================================================================
--- work.orig/fs/sysfs/dir.c
+++ work/fs/sysfs/dir.c
@@ -678,8 +678,10 @@ static struct dentry * sysfs_lookup(stru
sd = sysfs_find_dirent(parent_sd, dentry->d_name.name);

/* no such entry */
- if (!sd)
+ if (!sd) {
+ ret = ERR_PTR(-ENOENT);
goto out_unlock;
+ }

/* attach dentry and inode */
inode = sysfs_get_inode(sd);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/