On Fri, Apr 5, 2024 at 7:23 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > 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? Let's try again, rebased on current master: #syz test: https://github.com/amir73il/linux/ vfs-fixes Thanks, Amir.
