On Tue, Apr 05, 2016 at 01:55:23PM -0700, Hugh Dickins wrote: > zap_pmd_range()'s CONFIG_DEBUG_VM !rwsem_is_locked(&mmap_sem) BUG() > will be invalid with huge pagecache, in whatever way it is implemented: > truncation of a hugely-mapped file to an unhugely-aligned size would > easily hit it. We can reproduce this BUG() in the current Linus tree with DAX PMDs. Andrew, can you send this patch to Linus for inclusion in 4.7? Tested-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx> -- 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>