On Thu, 19 Dec 2013 09:58:05 +0900 Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> wrote: > On Wed, Dec 18, 2013 at 04:28:58PM -0800, Andrew Morton wrote: > > On Thu, 19 Dec 2013 08:16:35 +0800 Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx> wrote: > > > > > page_get_anon_vma() called in page_referenced_anon() will lock and > > > increase the refcount of anon_vma, page won't be locked for anonymous > > > page. This patch fix it by skip check anonymous page locked. > > > > > > [ 588.698828] kernel BUG at mm/rmap.c:1663! > > > > Why is all this suddenly happening. Did we change something, or did a > > new test get added to trinity? > > It is my fault. > I should remove this VM_BUG_ON() since rmap_walk() can be called > without holding PageLock() in this case. > > I think that adding VM_BUG_ON() to each rmap_walk calllers is better > than this patch, because, now, rmap_walk() is called by many places and > each places has different contexts. I don't think that putting the assertion into the caller makes a lot of sense, particularly if that code just did a lock_page()! If a *callee* needs PageLocked() then that callee should assert that the page is locked. So VM_BUG_ON(!PageLocked(page)); means "this code requires that the page be locked". And if that code requires PageLocked(), there must be reasons for this. Let's also include an explanation of those reasons. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>