[PATCH] sysfs: move assignment to be under lock in sysfs_remove_dir()

From: Greg KH
Date: Tue Oct 29 2013 - 18:09:44 EST


From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Linus noticed that the assignment of sd isn't protected by the lock in
sysfs_remove_dir(), so move the assignment of the variable under the
lock to be safe.

Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---

Tejun, any objection to this patch? You consolidated the locks back in
2007 on this function, and nothing has changed there since then, so odds
are it's not a problem, but nice to be safe, right?

fs/sysfs/dir.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index eab59de4..2609f934 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -856,9 +856,10 @@ void sysfs_remove(struct sysfs_dirent *sd)
*/
void sysfs_remove_dir(struct kobject *kobj)
{
- struct sysfs_dirent *sd = kobj->sd;
+ struct sysfs_dirent *sd;

spin_lock(&sysfs_assoc_lock);
+ sd = kobj->sd;
kobj->sd = NULL;
spin_unlock(&sysfs_assoc_lock);

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