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authorLinus Torvalds2022-11-18 10:49:53 -0800
committerLinus Torvalds2022-11-18 10:49:53 -0800
commit63c8c0d7dcb687c123ec6dc7e958cd54ebf956b6 (patch)
tree7d31f95b32fefe0ff0934d404aeb54200ad6efec /fs
parent1f63d1a106e98db5cd378b21a471f7ddd710d1b5 (diff)
parent1edfe4ea16ca2c9e91ec6cecd446b13636724e4f (diff)
Merge tag 'driver-core-6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH: "Here are two small driver core fixes for 6.1-rc6: - utsname fix, this one should already be in your tree as it came from a different tree earlier. - kernfs bugfix for a much reported syzbot report that seems to keep getting triggered. Both of these have been in linux-next for a while with no reported issues" * tag 'driver-core-6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: kernfs: Fix spurious lockdep warning in kernfs_find_and_get_node_by_id() kernel/utsname_sysctl.c: Add missing enum uts_proc value
Diffstat (limited to 'fs')
-rw-r--r--fs/kernfs/dir.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 3990f3e270cb..f33b3baad07c 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -31,10 +31,15 @@ static DEFINE_SPINLOCK(kernfs_idr_lock); /* root->ino_idr */
#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
+static bool __kernfs_active(struct kernfs_node *kn)
+{
+ return atomic_read(&kn->active) >= 0;
+}
+
static bool kernfs_active(struct kernfs_node *kn)
{
lockdep_assert_held(&kernfs_root(kn)->kernfs_rwsem);
- return atomic_read(&kn->active) >= 0;
+ return __kernfs_active(kn);
}
static bool kernfs_lockdep(struct kernfs_node *kn)
@@ -705,7 +710,12 @@ struct kernfs_node *kernfs_find_and_get_node_by_id(struct kernfs_root *root,
goto err_unlock;
}
- if (unlikely(!kernfs_active(kn) || !atomic_inc_not_zero(&kn->count)))
+ /*
+ * We should fail if @kn has never been activated and guarantee success
+ * if the caller knows that @kn is active. Both can be achieved by
+ * __kernfs_active() which tests @kn->active without kernfs_rwsem.
+ */
+ if (unlikely(!__kernfs_active(kn) || !atomic_inc_not_zero(&kn->count)))
goto err_unlock;
spin_unlock(&kernfs_idr_lock);