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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7F8DAC433FB for ; Tue, 14 Jul 2020 19:07:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4B82921D79 for ; Tue, 14 Jul 2020 19:07:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594753641; bh=iv8j59IizSFovtJeOSAaB86Jk9Z6jur6Paq2/nEHfOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dQOCGTISWuoOcXseHjJ2xIfHWjWCvJFcKoqrcLzIR2oOr1GsXnrO4zuMHyv1j4i0p sydyI/mjFMFMKA8nM78yodngLyzmCx3Tf8RpUkFdxmE1+peQV8o8frOKGOorIt0jsF jQUMeSanp4gkZ2Hm1n81aCKaUVDh/qmaBZKFhOi4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730075AbgGNSwZ (ORCPT ); Tue, 14 Jul 2020 14:52:25 -0400 Received: from mail.kernel.org ([198.145.29.99]:49136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730511AbgGNSwY (ORCPT ); Tue, 14 Jul 2020 14:52:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 81BB422B42; Tue, 14 Jul 2020 18:52:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752744; bh=iv8j59IizSFovtJeOSAaB86Jk9Z6jur6Paq2/nEHfOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fTjQleT0YE61FAUpMxBNDHU/uOjYvrMHPtX8J06celY8+9W9iWjz/VkvGkCPzcDnX psyhMS55CEkKJIqdEHHCbl711T5wS4d06NFV047rCWpHpWTmVjwwQ5bM2MxrBBJ+9o kGrqiCHJYciE5KEU57q+dCqHUaYCA41GGyjKeZm4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Josef Bacik , David Sterba Subject: [PATCH 5.4 094/109] btrfs: fix double put of block group with nocow Date: Tue, 14 Jul 2020 20:44:37 +0200 Message-Id: <20200714184110.060376603@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184105.507384017@linuxfoundation.org> References: <20200714184105.507384017@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Josef Bacik commit 230ed397435e85b54f055c524fcb267ae2ce3bc4 upstream. While debugging a patch that I wrote I was hitting use-after-free panics when accessing block groups on unmount. This turned out to be because in the nocow case if we bail out of doing the nocow for whatever reason we need to call btrfs_dec_nocow_writers() if we called the inc. This puts our block group, but a few error cases does if (nocow) { btrfs_dec_nocow_writers(); goto error; } unfortunately, error is error: if (nocow) btrfs_dec_nocow_writers(); so we get a double put on our block group. Fix this by dropping the error cases calling of btrfs_dec_nocow_writers(), as it's handled at the error label now. Fixes: 762bf09893b4 ("btrfs: improve error handling in run_delalloc_nocow") CC: stable@vger.kernel.org # 5.4+ Reviewed-by: Filipe Manana Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1657,12 +1657,8 @@ out_check: ret = fallback_to_cow(inode, locked_page, cow_start, found_key.offset - 1, page_started, nr_written); - if (ret) { - if (nocow) - btrfs_dec_nocow_writers(fs_info, - disk_bytenr); + if (ret) goto error; - } cow_start = (u64)-1; } @@ -1678,9 +1674,6 @@ out_check: ram_bytes, BTRFS_COMPRESS_NONE, BTRFS_ORDERED_PREALLOC); if (IS_ERR(em)) { - if (nocow) - btrfs_dec_nocow_writers(fs_info, - disk_bytenr); ret = PTR_ERR(em); goto error; }