From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750907AbdAPJs4 (ORCPT ); Mon, 16 Jan 2017 04:48:56 -0500 Received: from mail.kernel.org ([198.145.29.136]:60528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750817AbdAPJsz (ORCPT ); Mon, 16 Jan 2017 04:48:55 -0500 Date: Mon, 16 Jan 2017 11:48:51 +0200 From: Leon Romanovsky To: Borislav Petkov Cc: Michal Hocko , Vlastimil Babka , Linux MM , LKML Subject: Re: [PATCH] mm/slub: Add a dump_stack() to the unexpected GFP check Message-ID: <20170116094851.GD32481@mtr-leonro.local> References: <20170116091643.15260-1-bp@alien8.de> <20170116092840.GC32481@mtr-leonro.local> <20170116093702.tp7sbbosh23cxzng@pd.tnic> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="FFoLq8A0u+X9iRU8" Content-Disposition: inline In-Reply-To: <20170116093702.tp7sbbosh23cxzng@pd.tnic> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --FFoLq8A0u+X9iRU8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jan 16, 2017 at 10:37:02AM +0100, Borislav Petkov wrote: > On Mon, Jan 16, 2017 at 11:28:40AM +0200, Leon Romanovsky wrote: > > On Mon, Jan 16, 2017 at 10:16:43AM +0100, Borislav Petkov wrote: > > > From: Borislav Petkov > > > > > > We wanna know who's doing such a thing. Like slab.c does that. > > > > > > Signed-off-by: Borislav Petkov > > > --- > > > mm/slub.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/mm/slub.c b/mm/slub.c > > > index 067598a00849..1b0fa7625d6d 100644 > > > --- a/mm/slub.c > > > +++ b/mm/slub.c > > > @@ -1623,6 +1623,7 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) > > > flags &= ~GFP_SLAB_BUG_MASK; > > > pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", > > > invalid_mask, &invalid_mask, flags, &flags); > > > + dump_stack(); > > > > Will it make sense to change these two lines above to WARN(true, .....)? > > Should be equivalent. Almost, except one point - pr_warn and dump_stack have different log levels. There is a chance that user won't see pr_warn message above, but dump_stack will be always present. For WARN_XXX, users will always see message and stack at the same time. > > I'd even go a step further and make this a small inline function, > something like warn_unexpected_gfp(flags) or so and call it from both > from slab.c and slub.c. > > Depending on what mm folks prefer, that is. > > -- > Regards/Gruss, > Boris. > > Good mailing practices for 400: avoid top-posting and trim the reply. --FFoLq8A0u+X9iRU8 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkhr/r4Op1/04yqaB5GN7iDZyWKcFAlh8lwMACgkQ5GN7iDZy WKc/ug//TRYm9M+3WN58c19PyGTKU/HwVKA4lnDie6D4BGdkN/Ag/KJe5iZcz+2f KuUpOOSIrwHDnPMVt4phLVGbzAdKH6ccodLScBjfWEZ0ACYvi8cnVWGMpKoBeE3+ p/tXNg5l9M4GWtz51ECZWN+J+qQRFTRnmy2XEbQiIJ/xoM/AMIBTuUyKoej3txn9 3wSCF+XhdFsMHggn5Gz9O2a+fGdkUF5RTMkMPk/Nh8JldhYJYfPj94vGzIlkdsMN +tpccX6B/D4hEvXzxw62ObkxP+G5nEkRcma89JIGKSlzc2oO6SfX/nt0TUXcAN1C N71lGBFTnbfuBHp4N70LUOuUFYm8uj2s2tO2RfNVPf850C/W9/87KjTgm3Kf49HZ xyyoM976O+F2/SGMti76XTct07tL9PdSeVdBrMI5Q9LZsdKnyMfDicN5oGik9Aak 6zbW4REGlGPueTFoBdBLi8iKeaGmS+PZcp9SOimED67Mzu5L+vj9q4+5pk0+wyl+ Gw+ydwvr62l0SbJrbWtcW/SVUSR9qyw+XDODVOWftSnO130YaxGHhjdVeuMRqF1T XItGDk5zHqKYpmZeuUX5X3mEBKBY3OwqZUYhuMNkDJVApkJ0Y4LW7awESiE+fxDv DpmcISxJLNoB/1Sp5qWeCgSo5e3LMu7XjPRZU1VLiwKZJR4LMn0= =BaMf -----END PGP SIGNATURE----- --FFoLq8A0u+X9iRU8--