From: Miklos Szeredi Date: Wed, 3 Aug 2016 11:44:27 +0000 (+0200) Subject: vfs: fix deadlock in file_remove_privs() on overlayfs X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c1892c37769cf89c7e7ba57528ae2ccb5d153c9b;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git vfs: fix deadlock in file_remove_privs() on overlayfs file_remove_privs() is called with inode lock on file_inode(), which proceeds to calling notify_change() on file->f_path.dentry. Which triggers the WARN_ON_ONCE(!inode_is_locked(inode)) in addition to deadlocking later when ovl_setattr tries to lock the underlying inode again. Fix this mess by not mixing the layers, but doing everything on underlying dentry/inode. Signed-off-by: Miklos Szeredi Fixes: 07a2daab49c5 ("ovl: Copy up underlying inode's ->i_mode to overlay inode") Cc: --- diff --git a/fs/inode.c b/fs/inode.c index 4ccbc21b30ce..68db39050446 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1740,8 +1740,8 @@ static int __remove_privs(struct dentry *dentry, int kill) */ int file_remove_privs(struct file *file) { - struct dentry *dentry = file->f_path.dentry; - struct inode *inode = d_inode(dentry); + struct dentry *dentry = file_dentry(file); + struct inode *inode = file_inode(file); int kill; int error = 0; @@ -1749,7 +1749,7 @@ int file_remove_privs(struct file *file) if (IS_NOSEC(inode)) return 0; - kill = file_needs_remove_privs(file); + kill = dentry_needs_remove_privs(dentry); if (kill < 0) return kill; if (kill)