| Message ID | 1573788472-87426-3-git-send-email-yukuai3@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fix potential infinite loop in debugfs_remove_recursive | expand |
diff --git a/fs/libfs.c b/fs/libfs.c index 1463b03..62e9ba9 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -336,9 +336,9 @@ int simple_empty(struct dentry *dentry) struct dentry *child; int ret = 0; - spin_lock(&dentry->d_lock); + spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); list_for_each_entry(child, &dentry->d_subdirs, d_child) { - spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); + spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED_2); if (simple_positive(child)) { spin_unlock(&child->d_lock); goto out;
simple_emtpty currently use 'spin_lock_nested' for 'child' to avoid confusion for lockdep. However, it's not used for 'dentry'. In that case, there will be a problem if the caller called 'simple_empty' with a parent's 'd_lock' held: spin_lock(&dentry->d_parent->d_lock) call simple_empty(dentry) spin_lock(&dentry->d_lock) --> lockdep will report this spin_lock_nested(child->d_lock, spin_lock_nested) spin_unlock(child_lock) spin_unlock($dentry->d_lock) return from simple_empty spin_unlock(&dentry->d_patrent->d_lock) So, use 'DENTRY_D_LOCK_NESTED' for 'dentry' and 'spin_lock_nested_2' for child. Signed-off-by: yu kuai <yukuai3@huawei.com> --- fs/libfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)