From mboxrd@z Thu Jan 1 00:00:00 1970 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 49F19C433F5 for ; Thu, 10 Feb 2022 23:19:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345584AbiBJXTd (ORCPT ); Thu, 10 Feb 2022 18:19:33 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:37186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244960AbiBJXTa (ORCPT ); Thu, 10 Feb 2022 18:19:30 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E75D7266C; Thu, 10 Feb 2022 15:19:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description; bh=5OxpglYg6sSOJNdELP8v+HgsOKFwOz/qsyk4a6rak9U=; b=Qd03c5MlqJEMYHC3hB/oWR/+TY aaWkCh/eC5fNwh5DPfDP3Rc5x+bI8revhAi/AIICmNUsk5jp0x4i1LJC0oAU0JjIPP5DpNjsqFiEi 4dr0jCuSBYgMBjtcouS2dzVyPLpc6hK+vcHrt+3c0+9UYJAlYVhcia4GHowFDNpwj7uM2jsBMjuDq LiqlmCpa6oFvUik4v8Yw36UE5i/NENSvhUomgRwLzP4zcxLYV4G5juD3I0SiuvE5sQFHgKOSkUlBN TNHm/U7rJCiJJTdIg+V+29DNxyH0UMWbNSN3awsu03/846D1rFKn6/pIBRcXTLskIq9fmCJw69iKN 8cZ4soTw==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nIIiT-0059e9-Ev; Thu, 10 Feb 2022 23:19:09 +0000 Date: Thu, 10 Feb 2022 15:19:09 -0800 From: Luis Chamberlain To: Stephen Rothwell , "Eric W. Biederman" , Tong Zhang Cc: Andrew Morton , Linus Torvalds , Domenico Andreoli , Tong Zhang , Linux Kernel Mailing List , Linux Next Mailing List Subject: Re: linux-next: boottime warning from todays linux-next Message-ID: References: <20220210184340.7eba108a@canb.auug.org.au> <20220210193302.686fa61a@canb.auug.org.au> <20220210214125.2b248790@canb.auug.org.au> <20220210222953.6e078d20@canb.auug.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20220210222953.6e078d20@canb.auug.org.au> Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 10, 2022 at 10:29:53PM +1100, Stephen Rothwell wrote: > Hi all, >=20 > On Thu, 10 Feb 2022 21:41:25 +1100 Stephen Rothwell wrote: > > > > On Thu, 10 Feb 2022 19:33:02 +1100 Stephen Rothwell wrote: > > > > > > On Thu, 10 Feb 2022 18:43:40 +1100 Stephen Rothwell wrote: =20 > > > > > > > > My qemu boot of a powerpc pseries_le_defconfig kernel produced these > > > > kernel messages: > > > >=20 > > > > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc3 #2 > > > > Call Trace: > > > > [c0000000073e3a80] [c0000000007bfd40] dump_stack_lvl+0x74/0xa8 (u= nreliable) > > > > [c0000000073e3ac0] [c00000000057e3dc] __register_sysctl_table+0x6= 0c/0x9f0 > > > > [c0000000073e3bd0] [c000000002041170] init_fs_stat_sysctls+0x48/0= x60 > > > > [c0000000073e3bf0] [c000000000012110] do_one_initcall+0x60/0x2d0 > > > > [c0000000073e3cd0] [c0000000020049f0] kernel_init_freeable+0x334/= 0x3dc > > > > [c0000000073e3db0] [c000000000012710] kernel_init+0x30/0x1a0 > > > > [c0000000073e3e10] [c00000000000cd64] ret_from_kernel_thread+0x5c= /0x64 > > > >=20 > > > > Presumably introduced by commit > > > >=20 > > > > b42bc9a3c511 ("Fix regression due to "fs: move binfmt_misc sysctl= to its own file"") =20 > > >=20 > > > OK, I cannot reproduce this with just Linus' tree. I will try to bis= ect. =20 OK so that's not the issue. > > It bisected to commit > >=20 > > 43a9443d5da2 ("Merge branch 'akpm-current/current'") > >=20 > > and both parents of that commit are fine :-( FWIW Linus merged a more newer version of the regression fix, and only until today did we get that version on linux-next. > So it seems that the parent of "fs/binfmt_misc" is a permanently empty > directory - the is_empty_dir() check in insert_header() succeeds. I am not seeing this issue on x86_64 KVM guest with: CONFIG_BINFMT_MISC=3Dm or CONFIG_BINFMT_MISC=3Dy I think the issue might be that linux-next has Andrew's earlier version of the fix merged, and Linus now has the new version. So linux-next has these extra things below. But I can't understand why this is seen on ppc and not on x86_64. diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 241cfc6bc36f..788b9a34d5ab 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2735,17 +2735,6 @@ static struct ctl_table vm_table[] =3D { { } }; =20 -static struct ctl_table fs_table[] =3D { -#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE) - { - .procname =3D "binfmt_misc", - .mode =3D 0555, - .child =3D sysctl_mount_point, - }, -#endif - { } -}; - static struct ctl_table debug_table[] =3D { #ifdef CONFIG_SYSCTL_EXCEPTION_TRACE { @@ -2765,7 +2754,6 @@ static struct ctl_table dev_table[] =3D { =20 DECLARE_SYSCTL_BASE(kernel, kern_table); DECLARE_SYSCTL_BASE(vm, vm_table); -DECLARE_SYSCTL_BASE(fs, fs_table); DECLARE_SYSCTL_BASE(debug, debug_table); DECLARE_SYSCTL_BASE(dev, dev_table); =20 @@ -2773,7 +2761,6 @@ int __init sysctl_init_bases(void) { register_sysctl_base(kernel); register_sysctl_base(vm); - register_sysctl_base(fs); register_sysctl_base(debug); register_sysctl_base(dev); =20