From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65EDDCD3430 for ; Tue, 19 Sep 2023 02:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230439AbjISCHg (ORCPT ); Mon, 18 Sep 2023 22:07:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230430AbjISCHe (ORCPT ); Mon, 18 Sep 2023 22:07:34 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EB3B10E for ; Mon, 18 Sep 2023 19:07:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.com; s=s31663417; t=1695089244; x=1695694044; i=quwenruo.btrfs@gmx.com; bh=oWFr/IWslf1Z/e9dvPtOwXq36IEw1+97UatQTvsXpKs=; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:Vw8wVnhVyLPVQNgOi8PefRx5fhoZG8ZMJx4mCQdHot9CDMUSrQE pA9C1Rgp/DkEFMnPg93Q1e1AUCL4SQjlgDR+llgN9BkNUPg4sFFxzRxu9W6aiP7rDZ9x5B+ X5j67YTzdYhHZYF7D657ylS/IcGuzM0nnltah92QiZJKDFjcJAQVNMXHvztgEd6eVXaiQbY ZIwSg2xgvQb6ifE5MtVmw== UI-OutboundReport: notjunk:1;M01:P0:mAGd4+3WhEM=;u0pzfiKP96NmDsHFx2jKZg35nKJ QKasNDbBG/LHlfJq4sGOV08IrWbGL8/fuSXlp8u5N6jaCV1MkkEIKkwaC0sIys5bVmKT0AhYG nlF7fqcbAvOUmmYbwfY/MD8m/xhJw0FGNI1ux/opq4HAMOYQDGoaF9m0qeNKcgzyJIJfLEVbA c/04LX56ptOI+g5GL/Anb0eamJByNrRlSpMO5haM4eITGYyWhvn/FREGj0zpPaTYWjbMkwuBp LVB7H8YX1Ai/75Zoah6XAqy8aO1sOg4e53MzNH11PiY4SagWaCWS57w4JedSFld10DW4TYT6r fNWaYwx3rN2oNIgpwF/6NkO2vF+JY1PAajD5qCPhsz6vU+1mNZ8rTBdpziSIrqWQY7mfKVOY7 WRp2SZeAkHk5G3I5fZWYZIw7hezujPejzIQtI91swr4Gvx/P9REVJ9YIGy1/yTt+tOcE6IYLi F59mZC8/yGco+67NKsA11O/O8wu+G7bMl2bNCEubyZxXWwP7Z55ks3pJeiz2Mhwc61EuuFg8w bQJsiPsfRvcdfzkzmy43mWsnxnhSwkulfIo6CkDitWaAyo+5GaNsEyebV2btPYNIdg922YCJJ P7Joq8/lLlkwPInh5vYYHLdod3l2yQIR93YL2wc9VxsE6XKHzSjalyEDWEyMQeGKU/9JRTYUW 8ZaugQQEt4xMyEFDpvXAxG4tdG+3sBiTaxBALaPTQWsaavENENcN+/QNJCDsQpAqLCK0UtVvG 7iW8X/uc+5Cqwmn0jTeDnFLrU/DLi1BaDdyeM01Hqqo2aU1WI4qRaMno7lZiu30XqViLaFOuw kVbFElWLjPjotE8dXO5Ngc53Rau0F3yz5wwJbbPaXBqb1rjDrO1IpdHx8ZiFoiUuT15uKZLx/ 4GVY8Baxa76CP5bGO8dbjBoI4lC6I/9hoStKi0LKfrEo+Pd7WQskIGPRjcTrJRPHwJQ3VV+2l Gz1NXrLIA3hFURED+9JQWQF0cD0= Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2023/9/19 02:27, David Sterba wrote: > On Sat, Sep 16, 2023 at 06:41:12AM +0930, Qu Wenruo wrote: >> >> >> On 2023/9/16 04:30, David Sterba wrote: >>> On Fri, Sep 15, 2023 at 10:10:13AM +0300, Dan Carpenter wrote: >>>> Hello Qu Wenruo, >>>> >>>> The patch f98b6215d7d1: "btrfs: extent_io: do extra check for extent >>>> buffer read write functions" from Aug 19, 2020 (linux-next), leads to >>>> the following Smatch static checker warning: >>>> >>>> fs/btrfs/print-tree.c:186 print_uuid_item() error: uninitialized symb= ol 'subvol_id'. >>>> fs/btrfs/tests/extent-io-tests.c:338 check_eb_bitmap() error: uniniti= alized symbol 'has'. >>>> fs/btrfs/tests/extent-io-tests.c:353 check_eb_bitmap() error: uniniti= alized symbol 'has'. >>>> fs/btrfs/uuid-tree.c:203 btrfs_uuid_tree_remove() error: uninitialize= d symbol 'read_subid'. >>>> fs/btrfs/uuid-tree.c:353 btrfs_uuid_tree_iterate() error: uninitializ= ed symbol 'subid_le'. >>>> fs/btrfs/uuid-tree.c:72 btrfs_uuid_tree_lookup() error: uninitialized= symbol 'data'. >>>> fs/btrfs/volumes.c:7415 btrfs_dev_stats_value() error: uninitialized = symbol 'val'. >>>> >>>> fs/btrfs/extent_io.c >>>> 4096 void read_extent_buffer(const struct extent_buffer *eb, voi= d *dstv, >>>> 4097 unsigned long start, unsigned long = len) >>>> 4098 { >>>> 4099 void *eb_addr =3D btrfs_get_eb_addr(eb); >>>> 4100 >>>> 4101 if (check_eb_range(eb, start, len)) >>>> 4102 return; >>>> ^^^^^^^ >>>> >>>> Originally this used to memset dstv to zero but now it just returns. >>>> I can easily just mark that error path as impossible. These days >>>> everyone with a brain zeros their stack variables anyway so it should= n't >>>> affect anyone who doesn't deserve it. >>> >>> Thanks, this explains the other errors reported on linux-next with >>> possibly uninitialized variables. >> >> Mind me to fix those uninitialized variables? >> Or should I just revert to the old behavior? > > I'd like to keep the branch in for-next so please fix the warnings. Unfortunately these warnings are not complete. I checked all the read_extent_buffer() callers, almost all of them needs some initialization. One example in split_item() of ctree.c: static noinline int split_item() { char *buf; buf =3D kmalloc(); read_extent_buffer(leaf, buf, ); } In above case, if the read range is invalid, then @buf is just garbage. I'm not sure if we should fix all call sites, it looks a little impractical (over 70 call sites). Thus I'd prefer to reset the target memory to zero if the range is invalid= . > Also > please s/continuous/contiguous/. We can then continue the discussion > regarding the allocator behaviour. I guess you're talking about the extent buffer allocator (going vm mapped memory to skip cross-page handling). However this patch is years old and already in upstream. Thanks, Qu