From c5020c5be9d266f66fa5ba3286f0e8d2d2265970 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 21 Feb 2025 09:42:32 +0100 Subject: [PATCH] kernfs: Move dput() outside of the RCU section. Al Viro pointed out that dput() might sleep and must not be invoked within an RCU section. Keep only find_next_ancestor() winthin the RCU section. Correct the wording in the comment. Fixes: 6ef5b6fae3040 ("kernfs: Drop kernfs_rwsem while invoking lookup_positive_unlocked().") Reported-by: Al Viro Signed-off-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/20250221084232.xksA_IQ4@linutronix.de Signed-off-by: Greg Kroah-Hartman --- fs/kernfs/mount.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c index f1cea282aae3..5124e196c2bf 100644 --- a/fs/kernfs/mount.c +++ b/fs/kernfs/mount.c @@ -222,17 +222,17 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn, root = kernfs_root(kn); /* * As long as kn is valid, its parent can not vanish. This is cgroup's - * kn so it not have its parent replaced. Therefore it is safe to use + * kn so it can't have its parent replaced. Therefore it is safe to use * the ancestor node outside of the RCU or locked section. */ if (WARN_ON_ONCE(!(root->flags & KERNFS_ROOT_INVARIANT_PARENT))) return ERR_PTR(-EINVAL); scoped_guard(rcu) { knparent = find_next_ancestor(kn, NULL); - if (WARN_ON(!knparent)) { - dput(dentry); - return ERR_PTR(-EINVAL); - } + } + if (WARN_ON(!knparent)) { + dput(dentry); + return ERR_PTR(-EINVAL); } do { -- 2.50.1