From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD5F9396B7D; Thu, 15 Jan 2026 16:53:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768495980; cv=none; b=TQL1aJPP1Pq5fW+AMmU1X1/ZO6gsRhnbmvqUTa5iwrVDqXAmonqC/VYpFDPYHiJsT4k+gzAQFE4o5tXQFFR4vaZfXp4a6c6r+VwyiPYekVdD0JpbNRqL9HGQM3M2z217pMXGwKoD3x2V/LmNSBpLN7wIXnYM3fZmHlah4G+ac3o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768495980; c=relaxed/simple; bh=aNqBlNyLkH6UK7Dfhac4v6ZgJ10c+hm4N01qrfXabZ8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=P853Y0BZmtJPtbqdW9GU70cRfjQeYRMVSCcjsg2BiuR/S39Xc+RZ2o1na2WAFr0zzov532mrD6jUO6VLCSKKNcAucKjbNAvYpTalMuVh3gYlT/0GK2s5GyMffltksYVwDwo/zQ6IObD+N8QHoqKgYpESmBf4SmMAlFeF7u9mmn0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=U3FBetpb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="U3FBetpb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38378C19421; Thu, 15 Jan 2026 16:53:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1768495980; bh=aNqBlNyLkH6UK7Dfhac4v6ZgJ10c+hm4N01qrfXabZ8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U3FBetpb3AC6HbtKO7l7qcCPqx/fYp2ni5Sd+kBFUmTcPkDkhn6vnEiIx/m8Bt9u3 Et+hTwU2T8S9hW2/gjQfNx3nl6tdF1pokEfSSvJk4xBF6tac3fFiwppq9W17HZ856T nXyofPnnHKXtACuhdNsb29D1E7t9+KhKedCAQAys= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, NeilBrown , Jeff Layton , Olga Kornievskaia , Chuck Lever Subject: [PATCH 6.18 004/181] nfsd: check that server is running in unlock_filesystem Date: Thu, 15 Jan 2026 17:45:41 +0100 Message-ID: <20260115164202.473129426@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260115164202.305475649@linuxfoundation.org> References: <20260115164202.305475649@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Olga Kornievskaia commit d0424066fcd294977f310964bed6f2a487fa4515 upstream. If we are trying to unlock the filesystem via an administrative interface and nfsd isn't running, it crashes the server. This happens currently because nfsd4_revoke_states() access state structures (eg., conf_id_hashtbl) that has been freed as a part of the server shutdown. [ 59.465072] Call trace: [ 59.465308] nfsd4_revoke_states+0x1b4/0x898 [nfsd] (P) [ 59.465830] write_unlock_fs+0x258/0x440 [nfsd] [ 59.466278] nfsctl_transaction_write+0xb0/0x120 [nfsd] [ 59.466780] vfs_write+0x1f0/0x938 [ 59.467088] ksys_write+0xfc/0x1f8 [ 59.467395] __arm64_sys_write+0x74/0xb8 [ 59.467746] invoke_syscall.constprop.0+0xdc/0x1e8 [ 59.468177] do_el0_svc+0x154/0x1d8 [ 59.468489] el0_svc+0x40/0xe0 [ 59.468767] el0t_64_sync_handler+0xa0/0xe8 [ 59.469138] el0t_64_sync+0x1ac/0x1b0 Ensure this can't happen by taking the nfsd_mutex and checking that the server is still up, and then holding the mutex across the call to nfsd4_revoke_states(). Reviewed-by: NeilBrown Reviewed-by: Jeff Layton Fixes: 1ac3629bf0125 ("nfsd: prepare for supporting admin-revocation of state") Cc: stable@vger.kernel.org Signed-off-by: Olga Kornievskaia Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4state.c | 5 ++--- fs/nfsd/nfsctl.c | 9 ++++++++- fs/nfsd/state.h | 4 ++-- 3 files changed, 12 insertions(+), 6 deletions(-) --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1759,7 +1759,7 @@ static struct nfs4_stid *find_one_sb_sti /** * nfsd4_revoke_states - revoke all nfsv4 states associated with given filesystem - * @net: used to identify instance of nfsd (there is one per net namespace) + * @nn: used to identify instance of nfsd (there is one per net namespace) * @sb: super_block used to identify target filesystem * * All nfs4 states (open, lock, delegation, layout) held by the server instance @@ -1771,9 +1771,8 @@ static struct nfs4_stid *find_one_sb_sti * The clients which own the states will subsequently being notified that the * states have been "admin-revoked". */ -void nfsd4_revoke_states(struct net *net, struct super_block *sb) +void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb) { - struct nfsd_net *nn = net_generic(net, nfsd_net_id); unsigned int idhashval; unsigned int sc_types; --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -259,6 +259,7 @@ static ssize_t write_unlock_fs(struct fi struct path path; char *fo_path; int error; + struct nfsd_net *nn; /* sanity check */ if (size == 0) @@ -285,7 +286,13 @@ static ssize_t write_unlock_fs(struct fi * 3. Is that directory the root of an exported file system? */ error = nlmsvc_unlock_all_by_sb(path.dentry->d_sb); - nfsd4_revoke_states(netns(file), path.dentry->d_sb); + mutex_lock(&nfsd_mutex); + nn = net_generic(netns(file), nfsd_net_id); + if (nn->nfsd_serv) + nfsd4_revoke_states(nn, path.dentry->d_sb); + else + error = -EINVAL; + mutex_unlock(&nfsd_mutex); path_put(&path); return error; --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -841,9 +841,9 @@ static inline void get_nfs4_file(struct struct nfsd_file *find_any_file(struct nfs4_file *f); #ifdef CONFIG_NFSD_V4 -void nfsd4_revoke_states(struct net *net, struct super_block *sb); +void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb); #else -static inline void nfsd4_revoke_states(struct net *net, struct super_block *sb) +static inline void nfsd4_revoke_states(struct nfsd_net *nn, struct super_block *sb) { } #endif