Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33A7CC433F5 for ; Wed, 12 Jan 2022 14:03:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353880AbiALODF (ORCPT ); Wed, 12 Jan 2022 09:03:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353879AbiALODC (ORCPT ); Wed, 12 Jan 2022 09:03:02 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2ED8C061756; Wed, 12 Jan 2022 06:03:01 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 91DEF60C02; Wed, 12 Jan 2022 14:03:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B50ABC36AEA; Wed, 12 Jan 2022 14:02:57 +0000 (UTC) Date: Wed, 12 Jan 2022 15:02:54 +0100 From: Christian Brauner To: Anders Roxell Cc: Naresh Kamboju , open list , Linux-Next Mailing List , lkft-triage@lists.linaro.org, LTP List , linux-fsdevel@vger.kernel.org, regressions@lists.linux.dev, containers@lists.linux.dev, Alexey Gladkov , Sven Schnelle , "Eric W. Biederman" , Alexander Viro , Arnd Bergmann Subject: Re: [next]: LTP: getxattr05.c:97: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28) Message-ID: <20220112140254.cvngcwggeevwaazw@wittgenstein> References: <20220112131837.igsjkkttqskw4eix@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 12, 2022 at 02:22:42PM +0100, Anders Roxell wrote: > On Wed, 12 Jan 2022 at 14:18, Christian Brauner > wrote: > > > > On Wed, Jan 12, 2022 at 05:15:37PM +0530, Naresh Kamboju wrote: > > > While testing LTP syscalls with Linux next 20220110 (and till date 20220112) > > > on x86_64, i386, arm and arm64 the following tests failed. > > > > > > tst_test.c:1365: TINFO: Timeout per run is 0h 15m 00s > > > getxattr05.c:87: TPASS: Got same data when acquiring the value of > > > system.posix_acl_access twice > > > getxattr05.c:97: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28) > > > tst_test.c:391: TBROK: Invalid child (13545) exit value 1 > > > > > > fanotify17.c:176: TINFO: Test #1: Global groups limit in privileged user ns > > > fanotify17.c:155: TFAIL: unshare(CLONE_NEWUSER) failed: ENOSPC (28) > > > tst_test.c:391: TBROK: Invalid child (14739) exit value 1 > > > > > > sendto03.c:48: TBROK: unshare(268435456) failed: ENOSPC (28) > > > > > > setsockopt05.c:45: TBROK: unshare(268435456) failed: ENOSPC (28) > > > > > > strace output: > > > -------------- > > > [pid 481] wait4(-1, 0x7fff52f5ae8c, 0, NULL) = -1 ECHILD (No child processes) > > > [pid 481] clone(child_stack=NULL, > > > flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, > > > child_tidptr=0x7f3af0fa7a10) = 483 > > > strace: Process 483 attached > > > [pid 481] wait4(-1, > > > [pid 483] unshare(CLONE_NEWUSER) = -1 ENOSPC (No space left on device) > > > > This looks like another regression in the ucount code. Reverting the > > following commit fixes it and makes the getxattr05 test work again: > > > > commit 0315b634f933b0f12cfa82660322f6186c1aa0f4 > > Author: Alexey Gladkov > > Date: Fri Dec 17 15:48:23 2021 +0100 > > > > ucounts: Split rlimit and ucount values and max values > > > > Since the semantics of maximum rlimit values are different, it would be > > better not to mix ucount and rlimit values. This will prevent the error > > of using inc_count/dec_ucount for rlimit parameters. > > > > This patch also renames the functions to emphasize the lack of > > connection between rlimit and ucount. > > > > v2: > > - Fix the array-index-out-of-bounds that was found by the lkp project. > > > > Reported-by: kernel test robot > > Signed-off-by: Alexey Gladkov > > Link: https://lkml.kernel.org/r/73ea569042babda5cee2092423da85027ceb471f.1639752364.git.legion@kernel.org > > Signed-off-by: Eric W. Biederman > > > > The issue only surfaces if /proc/sys/user/max_user_namespaces is > > actually written to. > > I did a git bisect and that pointed me to this patch too. Uhm, doesn't this want to be: diff --git a/kernel/ucount.c b/kernel/ucount.c index 22070f004e97..108c6a879cd8 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -264,7 +264,7 @@ long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v) long ret = 0; for (iter = ucounts; iter; iter = iter->ns->ucounts) { - long new = atomic_long_add_return(v, &iter->ucount[type]); + long new = atomic_long_add_return(v, &iter->rlimit[type]); if (new < 0 || new > max) ret = LONG_MAX; else if (iter == ucounts) @@ -279,7 +279,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v) struct ucounts *iter; long new = -1; /* Silence compiler warning */ for (iter = ucounts; iter; iter = iter->ns->ucounts) { - long dec = atomic_long_sub_return(v, &iter->ucount[type]); + long dec = atomic_long_sub_return(v, &iter->rlimit[type]); WARN_ON_ONCE(dec < 0); if (iter == ucounts) new = dec; otherwise, inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_NPROC, 1) means long inc_rlimit_ucounts(struct ucounts *ucounts, UCOUNT_RLIMIT_NPROC, long v) { struct ucounts *iter; long max = LONG_MAX; long ret = 0; for (iter = ucounts; iter; iter = iter->ns->ucounts) { long new = atomic_long_add_return(v, &iter->ucount[UCOUNT_RLIMIT_NPROC]); if (new < 0 || new > max) ret = LONG_MAX; else if (iter == ucounts) ret = new; max = get_userns_rlimit_max(iter->ns, UCOUNT_RLIMIT_NPROC); } return ret; } which means that UCOUNT_RLIMIT_NPROC overwrites ucount[UCOUNT_RLIMIT_NPROC]?