On Thu, Oct 18, 2018 at 11:41 AM Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > > On Thu, Oct 18, 2018 at 8:26 AM, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > > > Can someone tell me what the expected behavior of a nested > > mutex_lock_interruptible(&lock); ? > > > > Why does the reproducer only warn and not really deadlock. > > It is because that is considered the lesser evil? > > and obviously, then inner unlock releases the outer lock? > > No, it's not the same lock, just the same lock class (first one is > OVL_I(d_inode(old))->lock, the other is > OVL_I(d_inode(new->d_parent)))->lock). Doh! of course. > > So we could possibly get away with annotating with > mutex_lock_nested(). Is this the only place that ovl_i_lock is > nested? > As far as I can see it is. But how would we annotate it for consistent and clear locking order? NLINK/COPYUP? if we want this annotation to maintain locking order we need to patch I posted (does copyup of new->parent prior to nlink_start), so then we don't need nested annotations anymore. Nah, I don't think we need to add nested annotations. FYI, I am working on a small cleanup series for ovl_nlink_start/end and ovl_inode_lock/unlock, but it is independent of the fix patch I posted for this bug. Thanks, Amir.
