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 E24F5379C5A; Wed, 12 Aug 2026 19:38:47 +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=1786563529; cv=none; b=ENNc0L9zK8SiQYFCNlFgsITvpzsBzifGX14a/FY0WKlVSRRt46zAcGxktF+vzFJ1E5f1AZoQRfOM+xMygZvN/FOw+lD8WU37abhStDan1dcS+IZIsAQUoCoK1GSANL1ALn046MIqlePsCFua7ryMg5isUkU8g4x1Zet4URK4uCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786563529; c=relaxed/simple; bh=ugXtEJBhqYVSq49FYKqxYj6OKn86LCwyFIYptLKfjNI=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=ej49UJPSMmWCbjqRMnT0By5MCq9l8Ku14tl5J8VxF5zJDtoWzSAkpetsAyBwXwpnf2FqUsonSnoTiZb5qrQjo+XjjeRJxH60ZrQaGl6QQU2tJ0qSy3xWJsq8tOKGHRWht3d0/aWe53og10F5EW0AVGzH58Oni1TJsKd5TajuFgw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jM5stS/5; 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="jM5stS/5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DE541F00A3E; Wed, 12 Aug 2026 19:38:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786563527; bh=fY1odR5tBPaRoKaZzJPmVwfU0anzzYor7+ZetS4hr50=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=jM5stS/5Z6K/cum8vcEinIw4Dkuh/0DOlwFmGrW4Bw+IR+vrwYlNA/Krj2iHVOfcW ZeEQ/RJTpwpLEnxpUpCB0A80sVrEtKLP4LkG//7xoL/vapDjEp4+WnNVkmSJijloS3 o1NyZ4e+G7bB54llsPLqd47YLdQP0/mFhXjj0/JkA+m7ZnIIDJaoIw3O7Mig2vYi57 d8z1zFIaR4p3/uxpN5DbUIUcdLNRIsJQvR4Eli3g2n5k0xMOdbZHo2FxN3oQM3Gu89 0aZ99x7+tvcylCmdkgo6l4NLq0DnPQU49TqIlnE/bu0a1opAY13YCcpHB2XTbczYRT qWY/4d2lH8sZg== Message-ID: <26486c88075a0b1e3c1cb088fe97d39e0051b5d3.camel@kernel.org> Subject: Re: [PATCH v2 4/8] SUNRPC: undo partial rpcbind registrations when svc_register() fails From: Jeff Layton 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 , "J. Bruce Fields" , Shuah Khan Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Trond Myklebust , linux-kselftest@vger.kernel.org Date: Wed, 12 Aug 2026 15:38:44 -0400 In-Reply-To: References: <20260811-nfsd-nl-hang-v2-0-c0c92b3953c3@kernel.org> <20260811-nfsd-nl-hang-v2-4-c0c92b3953c3@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ 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CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-08-11 at 15:19 -0400, Chuck Lever wrote: >=20 > On Tue, Aug 11, 2026, at 8:03 AM, Jeff Layton wrote: > > svc_register() registers each [program, version] in turn. On failure th= e > > caller tears the listener down -- svc_setup_socket() frees the svc_sock= and > > svc_create_socket() releases the socket -- but the entries that were al= ready > > set stay in rpcbind, now pointing at a closed port. XPT_RPCB_UNREG is s= et > > later, in svc_udp_init()/svc_tcp_init(), so svc_delete_xprt() never run= s for > > this transport and nothing clears them. > >=20 > > Unwind on failure, and stop the walk there rather than registering the > > programs after it. rpcbind matches RPCBPROC_UNSET on > > [program, version, netid] and ignores the address, so the unwind clears= the > > netid, not just the port -- the same granularity svc_delete_xprt() alre= ady > > unregisters at. > >=20 > > Assisted-by: LLM > > Signed-off-by: Jeff Layton > > --- > > net/sunrpc/svc.c | 31 ++++++++++++++++++++++++++++++- > > 1 file changed, 30 insertions(+), 1 deletion(-) > >=20 > > diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c > > index 4f402bbf97ba..9ffa87007004 100644 > > --- a/net/sunrpc/svc.c > > +++ b/net/sunrpc/svc.c > > @@ -1183,6 +1183,29 @@ int svc_generic_rpcbind_set(struct net *net, > > } > > EXPORT_SYMBOL_GPL(svc_generic_rpcbind_set); > >=20 > > +/* > > + * Undo the [program, version] registrations that this svc_register()= =20 > > call > > + * already made, stopping at version @nvers of program @nprog. > > + * > > + * Note that rpcbind matches RPCBPROC_UNSET on [program, version,=20 > > netid] and > > + * ignores the address, so this clears the netid rather than the one= =20 > > port. > > + * That is the granularity svc_delete_xprt() unregisters at as well. > > + */ > > +static void svc_unwind_register(const struct svc_serv *serv, struct= =20 > > net *net, > > + const int family, const unsigned short proto, > > + unsigned int nprog, unsigned int nvers) > > +{ > > + unsigned int p, i; > > + > > + for (p =3D 0; p <=3D nprog; p++) { > > + struct svc_program *progp =3D &serv->sv_programs[p]; > > + unsigned int last =3D p < nprog ? progp->pg_nvers : nvers; > > + > > + for (i =3D 0; i < last; i++) > > + progp->pg_rpcbind_set(net, progp, i, family, proto, 0); > > + } > > +} >=20 > For an IPv4 listener, the port-zero callback falls back through > __svc_rpcb_register4() to rpcb_register(). PMAPPROC_UNSET ignores > its protocol argument, so unwinding a partially successful TCP > registration also removes the mappings for existing listeners on > other transports, I would think. >=20 > It might be that the best the kernel can do here is tear everything > down if one registration fails. >=20 What I was thinking for NFSv2/3 was to just have the listener set netlink call wait for registration to complete before returning to userland. That would mean we'd have to block even longer to try and unregister things if things fail. Alternate proposal: let's just declare rpcbind reg errors to be non- fatal: do a pr_warn() and just leave it up to the admin to sort it out if that happens instead of trying to fail the startup. The resulting situation for the server is no worse off (it's just running instead of being down), and I move that we're better off leaving it up to a human to clean up the mess instead of trying to fix things up from the kernel. Thoughts? --=20 Jeff Layton