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authorEric W. Biederman <ebiederm@xmission.com>2007-08-20 21:36:30 +0900
committerGreg Kroah-Hartman <gregkh@suse.de>2007-10-12 14:51:08 -0700
commit932ea2e374dd1ca26676297a5eccd1cdab86f7cd (patch)
tree83bba794de7f1f9f9290192f4f95a8ed9c91dfb6 /fs/sysfs/file.c
parent89bec09705d2033b8b765f3c3ac5093f80bd5bc4 (diff)
downloadvexpress-lsk-932ea2e374dd1ca26676297a5eccd1cdab86f7cd.tar.gz
sysfs: Introduce sysfs_rename_mutex
Looking carefully at the rename code we have a subtle dependency that the structure of sysfs not change while we are performing a rename. If the parent directory of the object we are renaming changes while the rename is being performed nasty things could happen when we go to release our locks. So introduce a sysfs_rename_mutex to prevent this highly unlikely theoretical issue. In addition hold sysfs_rename_mutex over all calls to sysfs_get_dentry. Allowing sysfs_get_dentry to be simplified in the future. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs/sysfs/file.c')
-rw-r--r--fs/sysfs/file.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 16f39c30b09..ff93c92164b 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -470,7 +470,9 @@ int sysfs_update_file(struct kobject * kobj, const struct attribute * attr)
if (!victim_sd)
goto out;
+ mutex_lock(&sysfs_rename_mutex);
victim = sysfs_get_dentry(victim_sd);
+ mutex_unlock(&sysfs_rename_mutex);
if (IS_ERR(victim)) {
rc = PTR_ERR(victim);
victim = NULL;
@@ -509,7 +511,9 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
if (!victim_sd)
goto out;
+ mutex_lock(&sysfs_rename_mutex);
victim = sysfs_get_dentry(victim_sd);
+ mutex_unlock(&sysfs_rename_mutex);
if (IS_ERR(victim)) {
rc = PTR_ERR(victim);
victim = NULL;