[v2] kernfs: fix missing kernfs_idr_lock to remove an ID from the IDR

[PATCH v2] kernfs: fix missing kernfs_idr_lock to remove an ID from the IDR

Posted by Muchun Song 2 years, 8 months ago

The root->ino_idr is supposed to be protected by kernfs_idr_lock, fix
it.

Fixes: 488dee96bb62 ("kernfs: allow creating kernfs objects with arbitrary uid/gid")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
v2:
 - Open code the locking.

 fs/kernfs/dir.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 45b6919903e6..5a1a4af9d3d2 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -655,7 +655,9 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
 	return kn;
 
  err_out3:
+	spin_lock(&kernfs_idr_lock);
 	idr_remove(&root->ino_idr, (u32)kernfs_ino(kn));
+	spin_unlock(&kernfs_idr_lock);
  err_out2:
 	kmem_cache_free(kernfs_node_cache, kn);
  err_out1:
-- 
2.11.0

Re: [PATCH v2] kernfs: fix missing kernfs_idr_lock to remove an ID from the IDR

Posted by Tejun Heo 2 years, 8 months ago

On Tue, May 23, 2023 at 10:40:17AM +0800, Muchun Song wrote:
> The root->ino_idr is supposed to be protected by kernfs_idr_lock, fix
> it.
> 
> Fixes: 488dee96bb62 ("kernfs: allow creating kernfs objects with arbitrary uid/gid")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun