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SubjectRe: [PATCH] sysfs: move assignment to be under lock in sysfs_remove_dir()
Greg KH <gregkh@linuxfoundation.org> writes:

> From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> 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.

I don't have a strong feeling either way but how would that matter?
There is only ever one sd associated with a kobj.

And we better be under the sysfs_mutex when the assignment and and
sysfs_remove_dir are called.

> Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
>
> 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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