On 08/26/2010 02:12 AM, Hugh Dickins wrote:
After several hours, kbuild tests hang with anon_vma_prepare() spinning on a newly allocated anon_vma's lock - on a box with CONFIG_TREE_PREEMPT_RCU=y (which makes this very much more likely, but it could happen without). The ever-subtle page_lock_anon_vma() now needs a further twist: since anon_vma_prepare() and anon_vma_fork() are liable to change the ->root of a reused anon_vma structure at any moment, page_lock_anon_vma() needs to check page_mapped() again before succeeding, otherwise page_unlock_anon_vma() might address a different root->lock. Signed-off-by: Hugh Dickins<hughd@xxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> And yes, AFAIK this code lived just in -mm up to now. -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>