From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794313309; b=Kr0xTTF1Ser7+qJ0grePrtRBT2u5Y9M58rhp9IE11cN+14Z/R8z3SLDxvgn53bQJ+2Ih 56ib1L+orcPeUcHeHRyGqz7APODeivtBVzUuAYQ4iaVQn7p0HVJxc5xiTMygeYWy9zB3b G0FdDE44jLLsZiFyr6E+3sXY7MMwlfbBcRMnoM2bkvwbVvA8DMRaqInH3mtbC/hrLYinl FOeQGZ/H9gHNd2ljVIauj7UFGptWyxi2o2dO0b6qn61RHi2YLSVKFVkThoSI4Wb+7K4Zn gMKeTWMl03YsRuAWBDnAQDAqDmMDFajU54/mcnJCuq+I2WazpdbirindEe3hI/LI5+Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794313309; h=Received:DKIM-Signature:Message-ID:Subject:From:To:Cc:Date: In-Reply-To:References:Autocrypt:Content-Type: Content-Transfer-Encoding:User-Agent:MIME-Version; bh=ILicECQ9zANN0An0v45y04zpUrUGB3SIAyGWP6qA6Mk=; b=k0SjAaGlcPArmfF3y4oxi9cVEf78Xi6gFVVsenQ3i5oY2KSdIOHoUP8oqiN5bQc6+XNx 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Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F6FF1F0089F; Tue, 10 Nov 2026 12:21:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794313308; bh=ILicECQ9zANN0An0v45y04zpUrUGB3SIAyGWP6qA6Mk=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=iZr+C+HsLndylzAK8sgjQuWsi/PR3RQXROFqUQiFg5KTC44IY3y+shcxYEyN/CmBv 8+HpWHWQPp3D+LXt5m+jJSUr8KojIMpLXvBr2lQY5uzRPK+j5tMg5m1n1aX4EZoLre wIRyu49/SvrDmD8mVii/VevwGyYQtlSPmEhldHRFC2rJrqPzDRyTfAzW/X1PO1mfhe 8hyLc6An2niCYDhDNH4zvJdl0NGM+E6CDmYNAISIGKytwZYKqs73+YY80GuK61RP2M upO+8J8ac1J3CJMskvB2cQYX8g9KLwrRLNB39VH/6sCv3fbK0hmcTjEvbciZszPwR/ v2Xo9XCLmKA0w== Message-ID: <991d7a98e92d0a28f5b750b0a04226ea1d3f938a.camel@kernel.org> Subject: Re: [PATCH] SUNRPC: Load the GSS module by OID only when the mechanism is missing From: Jeff Layton To: Sasha Levin , Chuck Lever , Trond Myklebust , Anna Schumaker Cc: NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , linux-nfs@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "kernelci.org bot" Date: Tue, 10 Nov 2026 07:21:36 -0500 In-Reply-To: <20261110030947.179738-1-sashal@kernel.org> References: <20261110030947.179738-1-sashal@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 cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf CBYyUE8QJpvTZyfUHNYldXlrjO6n5MdOempLqWpfOmcGkwnyNRBR46g/jf8KnPRwXs509yAqDB6sE 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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 (3.60.2-3.fc44) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 On Mon, 2026-11-09 at 22:09 -0500, Sasha Levin wrote: > gss_mech_get_by_OID() calls request_module() before it looks at the > list of registered mechanisms, so every lookup forks a modprobe, even > when the mechanism is already registered or built in. > gss_mech_get_by_name() and gss_mech_get_by_pseudoflavor() only load > the module when the lookup fails. >=20 > The read handler of /proc/net/rpc/gss_krb5_enctypes uses this lookup, > so every read() of that file runs modprobe, two per cat. The file is > present in every /proc//net/rpc and /proc//task//net/rpc > directory, and LTP read_all gives each read one second. On a slow board > in KernelCI its workers stall on this file and the test times out. >=20 > Look up the mechanism first and call request_module() only when it is > not found, as the other two lookup functions do. >=20 > Reported-by: kernelci.org bot > Closes: https://d.kernelci.org/test/maestro:6af225865b429d354e253b9b > Fixes: f783288f0cf4 ("SUNRPC: Load GSS kernel module by OID") > Signed-off-by: Sasha Levin > --- > net/sunrpc/auth_gss/gss_mech_switch.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) >=20 > diff --git a/net/sunrpc/auth_gss/gss_mech_switch.c b/net/sunrpc/auth_gss/= gss_mech_switch.c > index 78eab245f94a7..d8b6ff9505399 100644 > --- a/net/sunrpc/auth_gss/gss_mech_switch.c > +++ b/net/sunrpc/auth_gss/gss_mech_switch.c > @@ -157,14 +157,9 @@ struct gss_api_mech * gss_mech_get_by_name(const cha= r *name) > return gm; > } > =20 > -struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj) > +static struct gss_api_mech *_gss_mech_get_by_OID(struct rpcsec_gss_oid *= obj) > { > struct gss_api_mech *pos, *gm =3D NULL; > - char buf[32]; > - > - if (sprint_oid(obj->data, obj->len, buf, sizeof(buf)) < 0) > - return NULL; > - request_module("rpc-auth-gss-%s", buf); > =20 > rcu_read_lock(); > list_for_each_entry_rcu(pos, ®istered_mechs, gm_list) { > @@ -177,6 +172,22 @@ struct gss_api_mech *gss_mech_get_by_OID(struct rpcs= ec_gss_oid *obj) > } > } > rcu_read_unlock(); > + return gm; > +} > + > +struct gss_api_mech *gss_mech_get_by_OID(struct rpcsec_gss_oid *obj) > +{ > + struct gss_api_mech *gm; > + char buf[32]; > + > + if (sprint_oid(obj->data, obj->len, buf, sizeof(buf)) < 0) > + return NULL; > + > + gm =3D _gss_mech_get_by_OID(obj); > + if (!gm) { > + request_module("rpc-auth-gss-%s", buf); > + gm =3D _gss_mech_get_by_OID(obj); > + } > if (!gm) > trace_rpcgss_oid_to_mech(buf); > return gm; Nice catch! Reviewed-by: Jeff Layton