From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7F578550DDA; Mon, 31 Aug 2026 16:15:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788192955; cv=none; b=N0CunRwxNOrwEmsA62/llvwy2ksxeeiocmQ1vXso8BHhZUrUWEbfRb6HNTgqc/5x5oD2ikhXzNLoS5I3Mp2K4Q6/JmUDRV2oDs4HdGIXEhddJHn5x2bz7ISiMmzxQgjc8Ajp//1b5mj1rg+wLY/y9cg/5OXXUA8lepClfzhoAlc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788192955; c=relaxed/simple; bh=SM2OWu0XleC4V96J3z4sUV5Kxnkpd0r1e2rH1vibgkM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=NGxJaR0IEiifa4JZEy2ZMDdJtU5njNpE2EiQBkYzL6g1Zk2sjFiUVtk45gd4w4khBIWDrg3kF5muHIAefwoBaQCOZQprmOuvicehjkPbY5or6T4J7aA53relNf3XsVewUmA1NlJiN/+PiguHrUVgoAwgPGBMAqTApHF15cExLUk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fwgWil/u; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fwgWil/u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 974FE1F00A3E; Mon, 31 Aug 2026 16:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788192954; bh=l3TJj1IX1HGJ6W0nzGDz0cyAW5MqVKBuV0o+O9iQ0hc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=fwgWil/uXxR+/S3jSu34sjWlYb0l5BDlEOdaz3YoyscRflcvp9titEx9DOR7grorE xSl4A+AS5KTFndvkdewux7XWcS2IWKsRdlnKsTzAZvuCBEQf9VBjpzRD4FkFI3FMD0 ghb7yWZ5E9Iooju6dOkzu4pVFZ5Pu1/s76TmgzyahfeZSmcO65qL13oKgf0KkjYY49 kKh3rVOb2eKXsMo07Deb0uC8/TQMPx2uXcNekK+Y+tNtuL+fV6AooJYsS+pjwoIo4Y I3UBCekY32qwYmNqxqjD7YLGk92q2FAZTHyCkiFXV8r8Ed1wW7lKwaeJY9Xvqe9fRE u49Z8tXfViB4w== From: Jeff Layton Date: Mon, 31 Aug 2026 12:14:52 -0400 Subject: [PATCH v4 10/14] NFSD: stop registering with rpcbind after a failure in listener_set Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260831-nfsd-nl-hang-v4-10-0f4e89139409@kernel.org> References: <20260831-nfsd-nl-hang-v4-0-0f4e89139409@kernel.org> In-Reply-To: <20260831-nfsd-nl-hang-v4-0-0f4e89139409@kernel.org> To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Trond Myklebust , Anna Schumaker , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Shuah Khan Cc: Slawomir Stepien , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Trond Myklebust , linux-kselftest@vger.kernel.org, Jeff Layton X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3554; i=jlayton@kernel.org; h=from:subject:message-id; bh=SM2OWu0XleC4V96J3z4sUV5Kxnkpd0r1e2rH1vibgkM=; b=owEBbQKS/ZANAwAKAQAOaEEZVoIVAcsmYgBqlaik2cLP0QIoCX8xMhRugEP5bcqI8NQHwBqJD 2ifud/oaXGJAjMEAAEKAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCapWopAAKCRAADmhBGVaC FbHqD/4n8xtKqxf+Jrm+xW5wAD4L8iZtiqwD6FUrIjN0Zo33HX8pI+kRYNQL0JNQM8NSP4yyhk+ soE/gRW72iqlRh2r1gw0kUkGQgWNA+jTe69QEgTnKV1yL3m9dGfCtnpRJa2FNsa9mx5KMzVz7jJ ZNB0otZlK2qZaiX1u4MWhqpq6qFSLaynws+IeNCRHW1m+LoU85olYwFedjfuSrJZniUDZOj0u1l iV/EQFjTpSTvq5toKQBX0QUMzLp1uN/eDnuhBJAyyAncsfOMg0OO9TsU0uoV/8oN7XmDp/qKK8S L/e2PZV2PYlGdsdl/7aR2C3MyxCM+a5WRuut6HDG3wymtiudusczR+5gRex7b4uD5LEYG+Rvr5l A/eqQKMWJi53Z+YPGhe2mLuCBZAWIGVhY05IF5DC3ZdXWe20J+zjf1lSCTRAUsVcR7iddUz4gOY NuNJx+gVDeiLE9EF0bhCXGnnyozmGDcmiq7ZoPkQYChsxgOQKGmnITjxoA1koQs2oNP1FU4pbQB LVyH/YoW70RvZSFWEv5dQUfcK97xSH6cWq7fG1wD727ao7DzoYO9s3jgyugrryTONnvzrT51RBX HmWdkUitjPnLB7KDQf5DZGpEHgipdFyZEeHKOvua62lsERmxVVNQOcF2zH0FUsouEVAJnW6V/ci iwdwC7tildwEhuQ== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 nfsd_nl_listener_set_doit() calls svc_xprt_create_from_sa() once for each requested listener and passes flags of 0, so every listener registers with rpcbind on its own. A rpcbind that accepts the connection and never replies therefore costs one timeout for each entry. With the cap of 1024 entries the request can hold nfsd_mutex for about 34 minutes, which is roughly 17 times the hung-task threshold. One failure is enough to know that the next call will not fare better. Read svc_rpcb_failure_count() before the create loop, and pass SVC_SOCK_ANONYMOUS for the rest of the request once the count moves. Fixes: 16a471177496 ("NFSD: add listener-{set,get} netlink command") Assisted-by: LLM Link: https://syzkaller.appspot.com/bug?extid=c7eae0eb80858a2dba0f Suggested-by: Olga Kornievskaia Signed-off-by: Jeff Layton --- fs/nfsd/nfsctl.c | 33 +++++++++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 4 deletions(-) diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index 6cbdcee4b733..2256c53277b8 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -2092,7 +2092,9 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) const struct nlattr *bad_attr = NULL; struct svc_xprt *xprt, *tmp; const char *bad_xprt = NULL; + unsigned int rpcb_failures; const struct nlattr *attr; + bool skipped_rpcb = false; struct svc_serv *serv; LIST_HEAD(permsocks); struct nfsd_net *nn; @@ -2182,13 +2184,15 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) if (delete) svc_xprt_destroy_all(serv, net, false); + rpcb_failures = svc_rpcb_failure_count(serv); + /* walk list of addrs again, open any that still don't exist */ nlmsg_for_each_attr_type(attr, NFSD_A_SERVER_SOCK_ADDR, info->nlhdr, GENL_HDRLEN, rem) { struct nlattr *tb[NFSD_A_SOCK_MAX + 1]; const char *xcl_name; struct sockaddr *sa; - int ret; + int flags, ret; /* validated up front in nfsd_nl_validate_listeners() */ if (nla_parse_nested(tb, NFSD_A_SOCK_MAX, attr, @@ -2207,8 +2211,20 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) continue; } - ret = svc_xprt_create_from_sa(serv, xcl_name, net, sa, 0, + flags = skipped_rpcb ? SVC_SOCK_ANONYMOUS : 0; + ret = svc_xprt_create_from_sa(serv, xcl_name, net, sa, flags, current_cred()); + + if (!skipped_rpcb && + svc_rpcb_failure_count(serv) != rpcb_failures) { + skipped_rpcb = true; + if (ret < 0) + ret = svc_xprt_create_from_sa(serv, xcl_name, + net, sa, + SVC_SOCK_ANONYMOUS, + current_cred()); + } + /* always save the latest error */ if (ret < 0) { bad_attr = attr; @@ -2224,8 +2240,17 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb, struct genl_info *info) */ if (err) { NL_SET_BAD_ATTR(info->extack, bad_attr); - NL_SET_ERR_MSG_FMT(info->extack, "cannot create %s listener", - bad_xprt); + if (skipped_rpcb) + NL_SET_ERR_MSG_FMT(info->extack, + "cannot create %s listener; rpcbind did not answer", + bad_xprt); + else + NL_SET_ERR_MSG_FMT(info->extack, + "cannot create %s listener", + bad_xprt); + } else if (skipped_rpcb) { + NL_SET_ERR_MSG(info->extack, + "rpcbind did not answer, some listeners are not registered"); } if (!serv->sv_nrthreads && list_empty(&nn->nfsd_serv->sv_permsocks)) -- 2.55.0