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 CF8181E7C08; Thu, 1 May 2025 04:07:31 +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=1746072451; cv=none; b=BVmtnrpl/OoFuNPCEN5UMpYbPGoVbHT/bW6YKftXu4N+svDI8ykzZrHppd3t1ICtYqCZVR/r7vypKF2ww6M6dwwehL6ubQn1fGt6Ln0ig+8xtHcU6BBRhEhk9Y/WP2aXpbbZn+foSoCMQJ2cpSY6VCcsRDZ530QLMPHD9dTwfK0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746072451; c=relaxed/simple; bh=h0QzjVR0KjHpyA96CNoleotE0TFuZUMfC/CGf9mA1O4=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=D42sjQS8P4GQCBbjYzxQnREvkG5O2s5xEftzrdalzJtpXXnN4FeUc0HvQYUnSlJD/pBtJPR3EDbCsIsdHs3rTz9XQCu0BkgYqmDDunCoNAWCQXYCna2MDmnNgONdAPW945tGeX+43/22O46MfzVGapH8wGEwe+h6q7NfO361/R0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Vc0N5x/q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Vc0N5x/q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87EA4C4CEE3; Thu, 1 May 2025 04:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746072451; bh=h0QzjVR0KjHpyA96CNoleotE0TFuZUMfC/CGf9mA1O4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Vc0N5x/qPw6HfifSrdfU66XAtnr852y8QGzp5fhv1pEpfEGa8RhjqYc6B9IL5NBmd +iQo4MTIMk1HXAx5AkjDnvHuJvFcsIkWvXa+WlgbvSc++Wc+dTkaSYtWk6gz0On5YF orbbF2SpC3JFtWPbqBCDwwEkJQf3sgQpQ5xg0gSYVWHtUYAqZkG/NSzX+VKl6ETyVb BAPYDthtp2cseJxmoZP1SP7wjO/qHsn+MUx/pTbuLrFfs5aH8AqM5kFnnMt5uYy/7L agf5qgmkU7VTjGllI+a2tpet1sBcauxWeKYTg9UHE0KNtYse77JgpBl7FjtzHgefwB 7S3DNO2v+95bw== Message-ID: <0c4e532ed8b58f8253a14f8ed59d93523a096f16.camel@kernel.org> Subject: Re: [PATCH v6 08/10] net: add symlinks to ref_tracker_dir for netns From: Jeff Layton To: Kuniyuki Iwashima Cc: airlied@gmail.com, akpm@linux-foundation.org, andrew@lunn.ch, davem@davemloft.net, dri-devel@lists.freedesktop.org, edumazet@google.com, horms@kernel.org, intel-gfx@lists.freedesktop.org, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, kuba@kernel.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, nathan@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, qasdev00@gmail.com, rodrigo.vivi@intel.com, simona@ffwll.ch, tursulin@ursulin.net, tzimmermann@suse.de Date: Wed, 30 Apr 2025 21:07:20 -0700 In-Reply-To: <20250501035115.76182-1-kuniyu@amazon.com> References: <20250501035115.76182-1-kuniyu@amazon.com> 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 LZH+yWr9LQZEwARAQABtCVKZWZmIExheXRvbiA8amxheXRvbkBwb29jaGllcmVkcy5uZXQ+iQI7BB MBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCTpXWPAIZAQAKCRAADmhBGVaCFc65D/4 gBLNMHopQYgG/9RIM3kgFCCQV0pLv0hcg1cjr+bPI5f1PzJoOVi9s0wBDHwp8+vtHgYhM54yt43uI 7Htij0RHFL5eFqoVT4TSfAg2qlvNemJEOY0e4daljjmZM7UtmpGs9NN0r9r50W82eb5Kw5bc/r0km R/arUS2st+ecRsCnwAOj6HiURwIgfDMHGPtSkoPpu3DDp/cjcYUg3HaOJuTjtGHFH963B+f+hyQ2B rQZBBE76ErgTDJ2Db9Ey0kw7VEZ4I2nnVUY9B5dE2pJFVO5HJBMp30fUGKvwaKqYCU2iAKxdmJXRI ONb7dSde8LqZahuunPDMZyMA5+mkQl7kpIpR6kVDIiqmxzRuPeiMP7O2FCUlS2DnJnRVrHmCljLkZ Wf7ZUA22wJpepBligemtSRSbqCyZ3B48zJ8g5B8xLEntPo/NknSJaYRvfEQqGxgk5kkNWMIMDkfQO lDSXZvoxqU9wFH/9jTv1/6p8dHeGM0BsbBLMqQaqnWiVt5mG92E1zkOW69LnoozE6Le+12DsNW7Rj iR5K+27MObjXEYIW7FIvNN/TQ6U1EOsdxwB8o//Yfc3p2QqPr5uS93SDDan5ehH59BnHpguTc27Xi QQZ9EGiieCUx6Zh2ze3X2UW9YNzE15uKwkkuEIj60NvQRmEDfweYfOfPVOueC+iFifbQgSmVmZiBM YXl0b24gPGpsYXl0b25AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6V0q0CGwMGCwkIBwMCBhUIAgkKC wQWAgMBAh4BAheAAAoJEAAOaEEZVoIViKUQALpvsacTMWWOd7SlPFzIYy2/fjvKlfB/Xs4YdNcf9q LqF+lk2RBUHdR/dGwZpvw/OLmnZ8TryDo2zXVJNWEEUFNc7wQpl3i78r6UU/GUY/RQmOgPhs3epQC 3PMJj4xFx+VuVcf/MXgDDdBUHaCTT793hyBeDbQuciARDJAW24Q1RCmjcwWIV/pgrlFa4lAXsmhoa c8UPc82Ijrs6ivlTweFf16VBc4nSLX5FB3ls7S5noRhm5/Zsd4PGPgIHgCZcPgkAnU1S/A/rSqf3F LpU+CbVBDvlVAnOq9gfNF+QiTlOHdZVIe4gEYAU3CUjbleywQqV02BKxPVM0C5/oVjMVx3bri75n1 TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw 87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2 xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y +jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5d Hxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBM BAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4h N9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPep naQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQ RERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6 FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR 685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8Eew P8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0Xzh aKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyAnLqRgDgR+wTQ T6gMhr2IRsl+cp8gPHBwQ4uZMb+X00c/Amm9VfviT+BI7B66cnC7Zv6Gvmtu2rEjWDGWPqUgccB7h dMKnKDthkA227/82tYoFiFMb/NwtgGrn5n2vwJyKN6SEoygGrNt0SI84y6hEVbQlSmVmZiBMYXl0b 24gPGpsYXl0b25AcHJpbWFyeWRhdGEuY29tPokCOQQTAQIAIwUCU4xmKQIbAwcLCQgHAwIBBhUIAg kKCwQWAgMBAh4BAheAAAoJEAAOaEEZVoIV1H0P/j4OUTwFd7BBbpoSp695qb6HqCzWMuExsp8nZjr uymMaeZbGr3OWMNEXRI1FWNHMtcMHWLP/RaDqCJil28proO+PQ/yPhsr2QqJcW4nr91tBrv/MqItu AXLYlsgXqp4BxLP67bzRJ1Bd2x0bWXurpEXY//VBOLnODqThGEcL7jouwjmnRh9FTKZfBDpFRaEfD FOXIfAkMKBa/c9TQwRpx2DPsl3eFWVCNuNGKeGsirLqCxUg5kWTxEorROppz9oU4HPicL6rRH22Ce 6nOAON2vHvhkUuO3GbffhrcsPD4DaYup4ic+DxWm+DaSSRJ+e1yJvwi6NmQ9P9UAuLG93S2MdNNbo sZ9P8k2mTOVKMc+GooI9Ve/vH8unwitwo7ORMVXhJeU6Q0X7zf3SjwDq2lBhn1DSuTsn2DbsNTiDv qrAaCvbsTsw+SZRwF85eG67eAwouYk+dnKmp1q57LDKMyzysij2oDKbcBlwB/TeX16p8+LxECv51a sjS9TInnipssssUDrHIvoTTXWcz7Y5wIngxDFwT8rPY3EggzLGfK5Zx2Q5S/N0FfmADmKknG/D8qG IcJE574D956tiUDKN4I+/g125ORR1v7bP+OIaayAvq17RP+qcAqkxc0x8iCYVCYDouDyNvWPGRhbL UO7mlBpjW9jK9e2fvZY9iw3QzIPGKtClKZWZmIExheXRvbiA8amVmZi5sYXl0b25AcHJpbWFyeWRh dGEuY29tPokCOQQTAQIAIwUCU4xmUAIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEAAOa EEZVoIVzJoQALFCS6n/FHQS+hIzHIb56JbokhK0AFqoLVzLKzrnaeXhE5isWcVg0eoV2oTScIwUSU apy94if69tnUo4Q7YNt8/6yFM6hwZAxFjOXR0ciGE3Q+Z1zi49Ox51yjGMQGxlakV9ep4sV/d5a50 M+LFTmYSAFp6HY23JN9PkjVJC4PUv5DYRbOZ6Y1+TfXKBAewMVqtwT1Y+LPlfmI8dbbbuUX/kKZ5d dhV2736fgyfpslvJKYl0YifUOVy4D1G/oSycyHkJG78OvX4JKcf2kKzVvg7/Rnv+AueCfFQ6nGwPn 0P91I7TEOC4XfZ6a1K3uTp4fPPs1Wn75X7K8lzJP/p8lme40uqwAyBjk+IA5VGd+CVRiyJTpGZwA0 jwSYLyXboX+Dqm9pSYzmC9+/AE7lIgpWj+3iNisp1SWtHc4pdtQ5EU2SEz8yKvDbD0lNDbv4ljI7e flPsvN6vOrxz24mCliEco5DwhpaaSnzWnbAPXhQDWb/lUgs/JNk8dtwmvWnqCwRqElMLVisAbJmC0 BhZ/Ab4sph3EaiZfdXKhiQqSGdK4La3OTJOJYZphPdGgnkvDV9Pl1QZ0ijXQrVIy3zd6VCNaKYq7B AKidn5g/2Q8oio9Tf4XfdZ9dtwcB+bwDJFgvvDYaZ5bI3ln4V3EyW5i2NfXazz/GA/I/ZtbsigCFc 8ftCBKZWZmIExheXRvbiA8amxheXRvbkBrZXJuZWwub3JnPokCOAQTAQIAIgUCWe8u6AIbAwYLCQg HAwIGFQgCCQoLBBYCAwECHgECF4AACgkQAA5oQRlWghUuCg/+Lb/xGxZD2Q1oJVAE37uW308UpVSD 2tAMJUvFTdDbfe3zKlPDTuVsyNsALBGclPLagJ5ZTP+Vp2irAN9uwBuacBOTtmOdz4ZN2tdvNgozz uxp4CHBDVzAslUi2idy+xpsp47DWPxYFIRP3M8QG/aNW052LaPc0cedYxp8+9eiVUNpxF4SiU4i9J DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD 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 3.54.3 (3.54.3-1.fc41) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2025-04-30 at 20:50 -0700, Kuniyuki Iwashima wrote: > From: Jeff Layton > Date: Wed, 30 Apr 2025 20:42:40 -0700 > > On Wed, 2025-04-30 at 20:07 -0700, Kuniyuki Iwashima wrote: > > > From: Jeff Layton > > > Date: Wed, 30 Apr 2025 19:59:23 -0700 > > > > On Wed, 2025-04-30 at 14:29 -0700, Kuniyuki Iwashima wrote: > > > > > From: Jeff Layton > > > > > Date: Wed, 30 Apr 2025 08:06:54 -0700 > > > > > > After assigning the inode number to the namespace, use it to cr= eate a > > > > > > unique name for each netns refcount tracker with the ns.inum va= lue in > > > > > > it, and register a symlink to the debugfs file for it. > > > > > >=20 > > > > > > init_net is registered before the ref_tracker dir is created, s= o add a > > > > > > late_initcall() to register its files and symlinks. > > > > > >=20 > > > > > > Signed-off-by: Jeff Layton > > > > > > --- > > > > > > net/core/net_namespace.c | 28 +++++++++++++++++++++++++++- > > > > > > 1 file changed, 27 insertions(+), 1 deletion(-) > > > > > >=20 > > > > > > diff --git a/net/core/net_namespace.c b/net/core/net_namespace.= c > > > > > > index 008de9675ea98fa8c18628b2f1c3aee7f3ebc9c6..6cbc8eabb8e56c8= 47fc34fa8ec9994e8b275b0af 100644 > > > > > > --- a/net/core/net_namespace.c > > > > > > +++ b/net/core/net_namespace.c > > > > > > @@ -763,12 +763,38 @@ struct net *get_net_ns_by_pid(pid_t pid) > > > > > > } > > > > > > EXPORT_SYMBOL_GPL(get_net_ns_by_pid); > > > > > > =20 > > > > > > +#ifdef CONFIG_NET_NS_REFCNT_TRACKER > > > > > > +static void net_ns_net_debugfs(struct net *net) > > > > > > +{ > > > > > > + ref_tracker_dir_symlink(&net->refcnt_tracker, "netns-%u-refcn= t", net->ns.inum); > > > > > > + ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%u-no= trefcnt", net->ns.inum); > > > > >=20 > > > > > Could you use net->net_cookie ? > > > > >=20 > > > > > net->ns.inum is always 1 when CONFIG_PROC_FS=3Dn. > > > >=20 > > > > My main use-case for this is to be able to match the inode number i= n > > > > the /proc//ns/net symlink with the correct ref_tracker debugfs > > > > file. Is there a way to use the net_cookie to make that association= ? > > >=20 > > > It's roundabout, but net_cookie can be retrieved by creating a > > > random socket in the netns and calling setsockopt(SO_NETNS_COOKIE). > > >=20 > > > Ido proposed a handy ip-netns subcommand here, and I guess it will > > > be implemented soon(?) > > > https://lore.kernel.org/netdev/1d99d7ccfc3a7a18840948ab6ba1c0b5fad909= 01.camel@fejes.dev/ > >=20 > > For the cases where I was looking at netns leaks, there were no more > > processes in the container, so there was no way to enter the container > > and spawn a socket at that point. >=20 > Then how do you get net->ns.inum ? >=20 In my case, I was looking at /sys/kernel/debug/sunrpc/rpc_xprt/*/info. That also displays net->ns.inum in the same format. When I was originally working on this, the problem I was chasing was due to stuck RPC transports (rpc_xprt). >=20 > >=20 > > The point of the symlinks is to have a way to easily identify what > > you're tracking. NAME_MAX is 255. We could do something like this > > instead: > >=20 > > snprintf(..., "netns-%u-%llx-refcnt", net->ns.inum, net->net_cookie)= ; > >=20 > > Obviously the inums would all be 1 when PROC_FS=3Dn, but the cookies > > would be unique. Would that work? >=20 > This works, but depending on the question above, there's no point in > using inum ? Having the inum is definitely useful to me, particularly since the net_cookie would be pretty useless for the problems I've been chasing. =20 I'll plan to respin this to include the net_cookie though, since that would disambiguate the names when PROC_FS=3Dn. It might also turn out to be useful for someone, once there is a way to fetch the net_cookie from userland.=20 --=20 Jeff Layton