On 08/19/2015 01:46 AM, Al Viro wrote: > On Mon, Aug 17, 2015 at 12:18:12PM +0300, Andrey Ryabinin wrote: > >> This bug is similar to recently found bug in 9p: http://thread.gmane.org/gmane.linux.kernel/1931799/focus=1936542 > > Ow. For those who'd missed that fun: the bug in question had turned out to > be caused by improper reuse of request ids, _not_ in the call chain of > the triggering syscall. > >> if (!retval) { >> struct iov_iter data = *iter; >> retval = mapping->a_ops->direct_IO(iocb, &data, pos); >> } >> >> if (retval > 0) { >> *ppos = pos + retval; >> iov_iter_advance(iter, retval); >> >> >> So either filemap_write_and_wait_range() > Shouldn't - it's supposed to return 0 or -E... > >> or mapping->a_ops->direct_IO() returned more >> than 'count'. > > Was there DAX involved? ->direct_IO() in there is blkdev_direct_IO(), > which takes rather different paths in those cases... I don't think so, at least I didn't configure it in. >>> Also too the file and line number >>> (lib/iov_iter.c:511) are completely useless because of inlining, >>> though that's not kasan's fault. > > Might make sense to slap > if (WARN_ON(size > iov_iter_count(i))) > print size and *i > and see if it triggers... It finally reproduced. size == 0x1000000, iov_iter_count(iter) == 0x1234. Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
