From patchwork Mon Mar 29 07:58:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 412761 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 F266BC433E5 for ; Mon, 29 Mar 2021 08:08:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B740D619A7 for ; Mon, 29 Mar 2021 08:08:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231534AbhC2IH7 (ORCPT ); Mon, 29 Mar 2021 04:07:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:49074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232345AbhC2IGe (ORCPT ); Mon, 29 Mar 2021 04:06:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 26BEC61932; Mon, 29 Mar 2021 08:06:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617005193; bh=+CSIDUoEPFTCArLXmqlLFa5UMXiV+bn7RaHR6vdETL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Quix/f8TgW0ypSoBVXnlzSHUq00lCLyPXiVt0ScsoH9cgNG1YJHdLyDHxrKla+sFZ K93XbBp/BpzB0iFiJz88uRYQWo4+47GxJLfj6cnxEdPF9yEGBOWXorD3fR6yIz6Rsz 5oWg3efsftXnKU5g5bxBl5CZlzBfzckz94Dkpkq0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Theodore Tso Subject: [PATCH 4.14 58/59] ext4: add reclaim checks to xattr code Date: Mon, 29 Mar 2021 09:58:38 +0200 Message-Id: <20210329075610.780311481@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210329075608.898173317@linuxfoundation.org> References: <20210329075608.898173317@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kara commit 163f0ec1df33cf468509ff38cbcbb5eb0d7fac60 upstream. Syzbot is reporting that ext4 can enter fs reclaim from kvmalloc() while the transaction is started like: fs_reclaim_acquire+0x117/0x150 mm/page_alloc.c:4340 might_alloc include/linux/sched/mm.h:193 [inline] slab_pre_alloc_hook mm/slab.h:493 [inline] slab_alloc_node mm/slub.c:2817 [inline] __kmalloc_node+0x5f/0x430 mm/slub.c:4015 kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x61/0xf0 mm/util.c:587 kvmalloc include/linux/mm.h:781 [inline] ext4_xattr_inode_cache_find fs/ext4/xattr.c:1465 [inline] ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1508 [inline] ext4_xattr_set_entry+0x1ce6/0x3780 fs/ext4/xattr.c:1649 ext4_xattr_ibody_set+0x78/0x2b0 fs/ext4/xattr.c:2224 ext4_xattr_set_handle+0x8f4/0x13e0 fs/ext4/xattr.c:2380 ext4_xattr_set+0x13a/0x340 fs/ext4/xattr.c:2493 This should be impossible since transaction start sets PF_MEMALLOC_NOFS. Add some assertions to the code to catch if something isn't working as expected early. Link: https://lore.kernel.org/linux-ext4/000000000000563a0205bafb7970@google.com/ Signed-off-by: Jan Kara Link: https://lore.kernel.org/r/20210222171626.21884-1-jack@suse.cz Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/xattr.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1479,6 +1479,9 @@ ext4_xattr_inode_cache_find(struct inode if (!ce) return NULL; + WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) && + !(current->flags & PF_MEMALLOC_NOFS)); + ea_data = ext4_kvmalloc(value_len, GFP_NOFS); if (!ea_data) { mb_cache_entry_put(ea_inode_cache, ce); @@ -2345,6 +2348,7 @@ ext4_xattr_set_handle(handle_t *handle, error = -ENOSPC; goto cleanup; } + WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS)); } error = ext4_reserve_inode_write(handle, inode, &is.iloc);