On Thu, Aug 3, 2017 at 4:25 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > On Thu, Aug 3, 2017 at 4:11 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: >> >> Where is this INIT_LIST_HEAD()? > > I think it's this one: > > list_del_init(&info->shrinklist); > > in shmem_unused_huge_shrink(). Yes, this is correct. Sorry about confusion. > >> I'm not sure I'm understanding this. AFAICT all the list operations to >> which you refer are synchronized under spin_lock(&sbinfo->shrinklist_lock)? > > No, notice how shmem_unused_huge_shrink() does the > > list_move(&info->shrinklist, &to_remove); > > and > > list_move(&info->shrinklist, &list); > > to move to (two different) private lists under the shrinklist_lock, > but once it is on that private "list/to_remove" list, it is then > accessed outside the locked region. > > Honestly, I don't love this situation, or the patch, but I think the > patch is likely the right thing to do. > Me neither. This is probably the quickest fix we could have, other possible changes might need much more work. Thanks. -- 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>
