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 75E2FCD37B0 for ; Mon, 18 Sep 2023 17:04:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230138AbjIRRE7 (ORCPT ); Mon, 18 Sep 2023 13:04:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59660 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231160AbjIRREf (ORCPT ); Mon, 18 Sep 2023 13:04:35 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D33C3192 for ; Mon, 18 Sep 2023 10:04:07 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 563702001F; Mon, 18 Sep 2023 17:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1695056646; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=cAzf71QvEYKSJEGcWDHFC6e+SPkSmPkG8pZx+Eus1bQ=; b=Z37TzTnpcDi7EDsInyNAyzmp7B8Aijg8deNgDF1SstYRBS8uVaZcqtZaVGbzNsaWor270l FOanUSWsNE3GvqfpCka1Ok6Pvy9npUGj1RKOTgBgHZ0OG8547WD7uQOOcMz8JmhOUcAsEz DD8myBkN3yl5gIsGTiecrosl5UA4Rok= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1695056646; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=cAzf71QvEYKSJEGcWDHFC6e+SPkSmPkG8pZx+Eus1bQ=; b=JO5KDTl3C2NrPxwxWIG7mGG2g6dNlzQru7MTq9haCGwRwXrBLz+r/20dvFPMBhQ1NKh5cD lzXfUeUvgDEgJKBQ== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 24F771358A; Mon, 18 Sep 2023 17:04:06 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ESlpCAaDCGWjDQAAMHmgww (envelope-from ); Mon, 18 Sep 2023 17:04:06 +0000 Date: Mon, 18 Sep 2023 18:57:30 +0200 From: David Sterba To: Qu Wenruo Cc: dsterba@suse.cz, Dan Carpenter , wqu@suse.com, linux-btrfs@vger.kernel.org Subject: Re: [bug report] btrfs: extent_io: do extra check for extent buffer read write functions Message-ID: <20230918165730.GK2747@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <20230915190047.GH2747@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org 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 symbol 'subvol_id'. > >> fs/btrfs/tests/extent-io-tests.c:338 check_eb_bitmap() error: uninitialized symbol 'has'. > >> fs/btrfs/tests/extent-io-tests.c:353 check_eb_bitmap() error: uninitialized symbol 'has'. > >> fs/btrfs/uuid-tree.c:203 btrfs_uuid_tree_remove() error: uninitialized symbol 'read_subid'. > >> fs/btrfs/uuid-tree.c:353 btrfs_uuid_tree_iterate() error: uninitialized 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, void *dstv, > >> 4097 unsigned long start, unsigned long len) > >> 4098 { > >> 4099 void *eb_addr = 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 shouldn'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. Also please s/continuous/contiguous/. We can then continue the discussion regarding the allocator behaviour.