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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 7CAE3C56202 for ; Wed, 25 Nov 2020 18:52:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DD9E20674 for ; Wed, 25 Nov 2020 18:52:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="EPRpyt5k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732902AbgKYSwq (ORCPT ); Wed, 25 Nov 2020 13:52:46 -0500 Received: from mail.kernel.org ([198.145.29.99]:58900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731511AbgKYSwp (ORCPT ); Wed, 25 Nov 2020 13:52:45 -0500 Received: from leira.hammer.space (c-68-36-133-222.hsd1.mi.comcast.net [68.36.133.222]) (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 04D5420674 for ; Wed, 25 Nov 2020 18:52:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606330365; bh=VAcHBRCuzZmQ32LgXpd9ndcKWoiJTPeWJo56L5v1+Uc=; h=From:To:Subject:Date:From; b=EPRpyt5k1c8Lfc7256g8FkFCCKM4Zg55/50ZGZC7Z/tffaVR3V7wOlYQ6fI8NgOUD ldbH3shl4KxpMSfdY4BilF/Zx3/rviwcRu/G2t0omXoDqJD2FC1qh9zmJTe8k+/9Fq MyeDJ8nOe1Qch17MC6vJo2x/SOnHqIwRpDjfev64= From: trondmy@kernel.org To: linux-nfs@vger.kernel.org Subject: [PATCH] NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode Date: Wed, 25 Nov 2020 13:52:40 -0500 Message-Id: <20201125185240.295065-1-trondmy@kernel.org> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Trond Myklebust When returning the layout in nfs4_evict_inode(), we need to ensure that the layout is actually done being freed before we can proceed to free the inode itself. Signed-off-by: Trond Myklebust --- fs/nfs/nfs4super.c | 2 +- fs/nfs/pnfs.c | 22 ++++++++++++++++++++-- fs/nfs/pnfs.h | 1 + 3 files changed, 22 insertions(+), 3 deletions(-) diff --git a/fs/nfs/nfs4super.c b/fs/nfs/nfs4super.c index 93f5c1678ec2..984cc42ee54d 100644 --- a/fs/nfs/nfs4super.c +++ b/fs/nfs/nfs4super.c @@ -67,7 +67,7 @@ static void nfs4_evict_inode(struct inode *inode) nfs_inode_evict_delegation(inode); /* Note that above delegreturn would trigger pnfs return-on-close */ pnfs_return_layout(inode); - pnfs_destroy_layout(NFS_I(inode)); + pnfs_destroy_layout_final(NFS_I(inode)); /* First call standard NFS clear_inode() code */ nfs_clear_inode(inode); nfs4_xattr_cache_zap(inode); diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 0e50b9d45c32..b4cc2059a5ba 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -294,6 +294,7 @@ void pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo) { struct inode *inode; + unsigned long i_state; if (!lo) return; @@ -304,8 +305,12 @@ pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo) if (!list_empty(&lo->plh_segs)) WARN_ONCE(1, "NFS: BUG unfreed layout segments.\n"); pnfs_detach_layout_hdr(lo); + i_state = inode->i_state; spin_unlock(&inode->i_lock); pnfs_free_layout_hdr(lo); + /* Notify pnfs_destroy_layout_final() that we're done */ + if (i_state & (I_FREEING | I_CLEAR)) + wake_up_var(lo); } } @@ -734,8 +739,7 @@ pnfs_free_lseg_list(struct list_head *free_me) } } -void -pnfs_destroy_layout(struct nfs_inode *nfsi) +static struct pnfs_layout_hdr *__pnfs_destroy_layout(struct nfs_inode *nfsi) { struct pnfs_layout_hdr *lo; LIST_HEAD(tmp_list); @@ -753,9 +757,23 @@ pnfs_destroy_layout(struct nfs_inode *nfsi) pnfs_put_layout_hdr(lo); } else spin_unlock(&nfsi->vfs_inode.i_lock); + return lo; +} + +void pnfs_destroy_layout(struct nfs_inode *nfsi) +{ + __pnfs_destroy_layout(nfsi); } EXPORT_SYMBOL_GPL(pnfs_destroy_layout); +void pnfs_destroy_layout_final(struct nfs_inode *nfsi) +{ + struct pnfs_layout_hdr *lo = __pnfs_destroy_layout(nfsi); + + if (lo) + wait_var_event(lo, nfsi->layout != lo); +} + static bool pnfs_layout_add_bulk_destroy_list(struct inode *inode, struct list_head *layout_list) diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index f618c49697bb..ef19499e1e0f 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -268,6 +268,7 @@ struct pnfs_layout_segment *pnfs_layout_process(struct nfs4_layoutget *lgp); void pnfs_layoutget_free(struct nfs4_layoutget *lgp); void pnfs_free_lseg_list(struct list_head *tmp_list); void pnfs_destroy_layout(struct nfs_inode *); +void pnfs_destroy_layout_final(struct nfs_inode *); void pnfs_destroy_all_layouts(struct nfs_client *); int pnfs_destroy_layouts_byfsid(struct nfs_client *clp, struct nfs_fsid *fsid, -- 2.28.0