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 2E9EAEEEC03 for ; Fri, 15 Sep 2023 19:08:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236963AbjIOTHq (ORCPT ); Fri, 15 Sep 2023 15:07:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33784 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237116AbjIOTH2 (ORCPT ); Fri, 15 Sep 2023 15:07:28 -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 22C1B10E for ; Fri, 15 Sep 2023 12:07:23 -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 C55C51F895; Fri, 15 Sep 2023 19:07:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1694804841; 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=m6WyrHto4MnBScauVuM7uKzl0VHSyghtVybUUjYtx+Y=; b=CgIfGNvAn2lL2b5S31swhdWLDqoBoJhRYO05WMHj5yycC7u4BjO4Uuq7hxEBzLwviTm7M5 3TTkQJ1q4lYNM92tgJcUoQswDiSWHxNAUeRJYSP74YAHs6byfToihms8PLO4L/BthKLyXV evTjmCIR29nwM8gbIElTLzxs2f2MiTg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1694804841; 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=m6WyrHto4MnBScauVuM7uKzl0VHSyghtVybUUjYtx+Y=; b=ruYdvAi5BESP4Xr3VNqoAPXtlWayh60dEW1uz62ETrBdrFYqIA++c7ji7cKBuOQtDz4ch2 3fUPIyfT/8y13tCA== 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 9815513251; Fri, 15 Sep 2023 19:07:21 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id wttEJGmrBGX4dAAAMHmgww (envelope-from ); Fri, 15 Sep 2023 19:07:21 +0000 Date: Fri, 15 Sep 2023 21:00:47 +0200 From: David Sterba To: Dan Carpenter Cc: 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: <20230915190047.GH2747@twin.jikos.cz> Reply-To: dsterba@suse.cz References: 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 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.