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 DF104C677F1 for ; Mon, 16 Jan 2023 16:21:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232829AbjAPQV0 (ORCPT ); Mon, 16 Jan 2023 11:21:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233029AbjAPQUh (ORCPT ); Mon, 16 Jan 2023 11:20:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD8EA2C64C for ; Mon, 16 Jan 2023 08:11:24 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D897661041 for ; Mon, 16 Jan 2023 16:11:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6FFEC433F2; Mon, 16 Jan 2023 16:11:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885483; bh=rtctP0Q22xvF7lObe+uv3DhkAqISm5KAV827JIFRjTo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qiTcVf6fAXQD+NgBzMHYEdDMyXfFPfcCi6fEIjFT8Xp8q2dseW10CZ6GTwheQ+rSk Q+2p/YMUsQLIr6t1W9EWeA+dVe8IiiPtAmLCK38loIrGlceUf5hQh3wCu++6Jfkrsm YtOnm0YS7wfoyY7ghDm3/1b+qqlGtAM8ATqPE+Pw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zhi Li , Jeff Layton , Chuck Lever , Sasha Levin Subject: [PATCH 5.4 069/658] nfsd: dont call nfsd_file_put from client states seqfile display Date: Mon, 16 Jan 2023 16:42:37 +0100 Message-Id: <20230116154912.790169201@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154909.645460653@linuxfoundation.org> References: <20230116154909.645460653@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jeff Layton [ Upstream commit e0aa651068bfd520afcd357af8ecd2de005fc83d ] We had a report of this: BUG: sleeping function called from invalid context at fs/nfsd/filecache.c:440 ...with a stack trace showing nfsd_file_put being called from nfs4_show_open. This code has always tried to call fput while holding a spinlock, but we recently changed this to use the filecache, and that started triggering the might_sleep() in nfsd_file_put. states_start takes and holds the cl_lock while iterating over the client's states, and we can't sleep with that held. Have the various nfs4_show_* functions instead hold the fi_lock instead of taking a nfsd_file reference. Fixes: 78599c42ae3c ("nfsd4: add file to display list of client's opens") Link: https://bugzilla.redhat.com/show_bug.cgi?id=2138357 Reported-by: Zhi Li Signed-off-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin --- fs/nfsd/nfs4state.c | 51 +++++++++++++++++++++++++++++---------------- 1 file changed, 33 insertions(+), 18 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 228c2b0753dc..de2c3809d15a 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -508,15 +508,26 @@ find_any_file(struct nfs4_file *f) return ret; } -static struct nfsd_file *find_deleg_file(struct nfs4_file *f) +static struct nfsd_file *find_any_file_locked(struct nfs4_file *f) { - struct nfsd_file *ret = NULL; + lockdep_assert_held(&f->fi_lock); + + if (f->fi_fds[O_RDWR]) + return f->fi_fds[O_RDWR]; + if (f->fi_fds[O_WRONLY]) + return f->fi_fds[O_WRONLY]; + if (f->fi_fds[O_RDONLY]) + return f->fi_fds[O_RDONLY]; + return NULL; +} + +static struct nfsd_file *find_deleg_file_locked(struct nfs4_file *f) +{ + lockdep_assert_held(&f->fi_lock); - spin_lock(&f->fi_lock); if (f->fi_deleg_file) - ret = nfsd_file_get(f->fi_deleg_file); - spin_unlock(&f->fi_lock); - return ret; + return f->fi_deleg_file; + return NULL; } static atomic_long_t num_delegations; @@ -2402,9 +2413,11 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) ols = openlockstateid(st); oo = ols->st_stateowner; nf = st->sc_file; - file = find_any_file(nf); + + spin_lock(&nf->fi_lock); + file = find_any_file_locked(nf); if (!file) - return 0; + goto out; seq_printf(s, "- 0x%16phN: { type: open, ", &st->sc_stateid); @@ -2422,8 +2435,8 @@ static int nfs4_show_open(struct seq_file *s, struct nfs4_stid *st) seq_printf(s, ", "); nfs4_show_owner(s, oo); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; } @@ -2437,9 +2450,10 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) ols = openlockstateid(st); oo = ols->st_stateowner; nf = st->sc_file; - file = find_any_file(nf); + spin_lock(&nf->fi_lock); + file = find_any_file_locked(nf); if (!file) - return 0; + goto out; seq_printf(s, "- 0x%16phN: { type: lock, ", &st->sc_stateid); @@ -2455,8 +2469,8 @@ static int nfs4_show_lock(struct seq_file *s, struct nfs4_stid *st) seq_printf(s, ", "); nfs4_show_owner(s, oo); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; } @@ -2468,9 +2482,10 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st) ds = delegstateid(st); nf = st->sc_file; - file = find_deleg_file(nf); + spin_lock(&nf->fi_lock); + file = find_deleg_file_locked(nf); if (!file) - return 0; + goto out; seq_printf(s, "- 0x%16phN: { type: deleg, ", &st->sc_stateid); @@ -2482,8 +2497,8 @@ static int nfs4_show_deleg(struct seq_file *s, struct nfs4_stid *st) nfs4_show_superblock(s, file); seq_printf(s, " }\n"); - nfsd_file_put(file); - +out: + spin_unlock(&nf->fi_lock); return 0; } -- 2.35.1