On Fri, Apr 05, 2024 at 08:37:03AM -0700, syzbot wrote: > Hello, > > syzbot tried to test the proposed patch but the build/boot failed: WTF? The patch is diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index e9df2f87072c6..8502ef68459b9 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -636,11 +636,18 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) * each file a separate locking class. Let's differentiate on * whether the file has mmap or not for now. * - * Both paths of the branch look the same. They're supposed to + * For similar reasons, writable and readonly files are given different + * lockdep key, because the writable file /sys/power/resume may call vfs + * lookup helpers for arbitrary paths and readonly files can be read by + * overlayfs from vfs helpers when sysfs is a lower layer of overalyfs. + * + * All three cases look the same. They're supposed to * look that way and give @of->mutex different static lockdep keys. */ if (has_mmap) mutex_init(&of->mutex); + else if (file->f_mode & FMODE_WRITE) + mutex_init(&of->mutex); else mutex_init(&of->mutex); How could it possibly trigger boot failure? Test the parent, perhaps?
