Hello, Jan. On Tue, Nov 29, 2016 at 10:30:35AM +0100, Jan Kara wrote: > > It's kinda weird that sync() is ends up accessing bdev's without any > > synchronization. Can't we just make iterate_bdevs() grab bd_mutex and > > verify bd_disk isn't NULL before calling into the callback? > > This reminded me I've already seen something like this and indeed I've > already had a very similar discussion in March - > https://patchwork.kernel.org/patch/8556941/ lol > Holding bd_mutex in iterate_devs() works but still nothing protects from > flusher thread just walking across the block device inode and trying to > write it which would result in the very same oops. Ah, right. We aren't implementing either sever or refcnted draining semantics properly. I wonder whether we'd be able to retire the inode synchronously during blkdev_put. Thanks. -- tejun -- 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>