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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73096C02181 for ; Wed, 22 Jan 2025 05:29:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 76DCB6B0082; Wed, 22 Jan 2025 00:29:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6F73D6B0083; Wed, 22 Jan 2025 00:29:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5498C6B0085; Wed, 22 Jan 2025 00:29:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 300F86B0082 for ; Wed, 22 Jan 2025 00:29:07 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 9FB741212E2 for ; Wed, 22 Jan 2025 05:29:06 +0000 (UTC) X-FDA: 83033959092.19.0111965 Received: from mailout1.samsung.com (mailout1.samsung.com [203.254.224.24]) by imf17.hostedemail.com (Postfix) with ESMTP id 4295940008 for ; Wed, 22 Jan 2025 05:29:02 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=samsung.com header.s=mail20170921 header.b=bJqr+9By; spf=pass (imf17.hostedemail.com: domain of hyesoo.yu@samsung.com designates 203.254.224.24 as permitted sender) smtp.mailfrom=hyesoo.yu@samsung.com; dmarc=pass (policy=none) header.from=samsung.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1737523744; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=jTIgUOPjSWcbxMsg66MPFxAGq89eHvU6LCFppmUWqNw=; b=qwEyFfUHT3rzkv0iG4l3snrbicxdJLbIgoHjhcchOfRmQKOSjc8mw++xa72NJAzqDZCNNw SoUResh4gMFDu3z3FUzx7VdleNErYRVhcDoOZNnnObaywcu086029sUWlniMpXQvStvMZR ZacFK62olbsvDrqBFonojVTgHMfO8i8= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=samsung.com header.s=mail20170921 header.b=bJqr+9By; spf=pass (imf17.hostedemail.com: domain of hyesoo.yu@samsung.com designates 203.254.224.24 as permitted sender) smtp.mailfrom=hyesoo.yu@samsung.com; dmarc=pass (policy=none) header.from=samsung.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1737523744; a=rsa-sha256; cv=none; b=XxWemOso4AqSWHAHHcGxR1rgdkT4USgUvTHGRI61/UgpqfYiKH2XzsoNUS1xeO2PZrljLT g6aQkQVY0abuiyHNX/c9E1fxJVupAWZWsqewcI7E+pBEqE+s53HbkOsi9ovhvg/Ib+v/WA muKUsF9/wYAWZk6B2TW1SR4SdfazjRs= Received: from epcas2p3.samsung.com (unknown [182.195.41.55]) by mailout1.samsung.com (KnoxPortal) with ESMTP id 20250122052859epoutp017d0cd78c40514c782fa0af8f24c4a634~c7KK6oapo0165601656epoutp01e for ; Wed, 22 Jan 2025 05:28:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.samsung.com 20250122052859epoutp017d0cd78c40514c782fa0af8f24c4a634~c7KK6oapo0165601656epoutp01e DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1737523739; bh=jTIgUOPjSWcbxMsg66MPFxAGq89eHvU6LCFppmUWqNw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bJqr+9ByMkACJeIlyzGIeDTeUcDFJBYykl0Lhz2z2RnukS8g3P6NpTeRASYsbPH8J 4KXGsJZPC3CT1QpJtRT68OcDKahaZabIoLOdTIRt2HeL8SLFqhGUARsePYR1HWVDMd fRCoZqkf0XqsA6iSmE62JF804VP52/cgrfkHjovc= Received: from epsnrtp1.localdomain (unknown [182.195.42.162]) by epcas2p1.samsung.com (KnoxPortal) with ESMTP id 20250122052859epcas2p1486f9a0fd4dd5873449b60f626eecf29~c7KKjaOGE3035230352epcas2p1b; Wed, 22 Jan 2025 05:28:59 +0000 (GMT) Received: from epsmges2p3.samsung.com (unknown [182.195.36.92]) by epsnrtp1.localdomain (Postfix) with ESMTP id 4YdCL26ftSz4x9Q1; Wed, 22 Jan 2025 05:28:58 +0000 (GMT) Received: from epcas2p1.samsung.com ( [182.195.41.53]) by epsmges2p3.samsung.com (Symantec Messaging Gateway) with SMTP id EF.D7.22105.A1280976; Wed, 22 Jan 2025 14:28:58 +0900 (KST) Received: from epsmtrp1.samsung.com (unknown [182.195.40.13]) by epcas2p4.samsung.com (KnoxPortal) with ESMTPA id 20250122052858epcas2p4cac06ba9cd5db34cfd1e9b051a22f913~c7KJUuifU0107801078epcas2p4k; Wed, 22 Jan 2025 05:28:58 +0000 (GMT) Received: from epsmgms1p2new.samsung.com (unknown [182.195.42.42]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20250122052858epsmtrp142b3c7e0054b59e075522f0489901242~c7KJT4NJ11245112451epsmtrp1q; Wed, 22 Jan 2025 05:28:58 +0000 (GMT) X-AuditID: b6c32a47-fd1c970000005659-18-6790821a19a6 Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p2new.samsung.com (Symantec Messaging Gateway) with SMTP id B0.96.18949.A1280976; Wed, 22 Jan 2025 14:28:58 +0900 (KST) Received: from tiffany (unknown [10.229.95.142]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20250122052857epsmtip27724b5ab400d29e4fc920d56c7207f01~c7KJEayWJ1739317393epsmtip2K; Wed, 22 Jan 2025 05:28:57 +0000 (GMT) Date: Wed, 22 Jan 2025 14:27:36 +0900 From: Hyesoo Yu To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: janghyuck.kim@samsung.com, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Chengming Zhou Subject: Re: [PATCH] mm: slub: Print the broken data before restoring slub. Message-ID: <20250122052736.GA1498496@tiffany> MIME-Version: 1.0 In-Reply-To: X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrOJsWRmVeSWpSXmKPExsWy7bCmqa5U04R0g7P9xhYTewws5qxfw2ax 8cwnVovr394wWqzsbmaz2Dyn2OLyrjlsFvfW/Ge1aPv8D0gs2chkMXGNqMXsxj5GBx6PnbPu snss2FTqsWlVJ5vHpk+T2D263l5h8jgx4zeLx5Mr05k8FjZMZfbo27KK0ePMgiPsHp83yQVw R2XbZKQmpqQWKaTmJeenZOal2yp5B8c7x5uaGRjqGlpamCsp5CXmptoqufgE6Lpl5gBdrqRQ lphTChQKSCwuVtK3synKLy1JVcjILy6xVUotSMkpMC/QK07MLS7NS9fLSy2xMjQwMDIFKkzI zpi6IKTgk3jF16tbWBoYvwh1MXJySAiYSJz79p+1i5GLQ0hgB6PEpa4uJgjnE6PEvn8XmSGc b4wSe3d8Ye9i5ABred4jDRHfyygx6c0WdgjnKaPEmuftbCBzWQRUJT603GEEsdkE1CVObFkG ZosA2Utuz2UFsZkFepkl9v7UBxkqLOAtsfKhPUiYV0BP4tvL3WwQtqDEyZlPWEBsToFAibeL QMZwAd1whkNiSt8JFogfXCSmTprBBGELS7w6DnIQiC0l8bK/Dcoulti2+DATRHMDo8TmjvvM EAljiVnP2hkhDsqU2PfgOzPEl8oSR26xQIT5JDoO/4V6nleiow0adMoS+5fNgzpBUuLR2nZW CNtDom/mLLC1QgLXGSWe3NKbwCg3C8k7s5AsmwU0lVlAU2L9Ln2IsLxE89bZUGFpieX/OJBU LGBkW8UollpQnJueWmxUYAyP6eT83E2M4BSt5b6DccbbD3qHGJk4GA8xSnAwK4nwin7oSRfi TUmsrEotyo8vKs1JLT7EaAqMpYnMUqLJ+cAskVcSb2hiaWBiZmZobmRqYK4kzlu9oyVdSCA9 sSQ1OzW1ILUIpo+Jg1Oqgck8oy5Kf0rzVOl5XxblRVSf2spdYCDfm7pRidP5i4ln0twor1P6 fSxRcZL939XFPvI+uRjc67PUk+vkYZ2srdHfZ1QkJWUoCe6vZN0kPHPu58v1k/2Wve5y/7Si KftDeF7XSo9NSn3+a7eqifr6M7HeESv2vPXh0UQrmdR7jfP/cz2de0qwv+jOr9dKEeJJ7kyz Kz9/mfFSbck/mTYxTocghbQWu2fFu0sF9TgrFZWOJx7ibb0uyr8med/C6B0vAtQ4j1ZGJxot 3/iKJeKKXOlz7uYjso75XHGinrxKrs2/Vr6XnaZb/MBSd16Uc8kDkRWefnM+P+l0XCCvJ7X/ eb/rc/6VJxTZ/1ZMOLtKiaU4I9FQi7moOBEAvpZiv1oEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprFIsWRmVeSWpSXmKPExsWy7bCSvK5U04R0g2/drBYTewws5qxfw2ax 8cwnVovr394wWqzsbmaz2Dyn2OLyrjlsFvfW/Ge1aPv8D0gs2chkMXGNqMXsxj5GBx6PnbPu snss2FTqsWlVJ5vHpk+T2D263l5h8jgx4zeLx5Mr05k8FjZMZfbo27KK0ePMgiPsHp83yQVw R3HZpKTmZJalFunbJXBlLNn4nK1gomhF+8S/TA2M6wW6GDk4JARMJJ73SHcxcnIICexmlPj3 mR/ElhCQlJj1+SQThC0scb/lCGsXIxdQzWNGiadLTjKCJFgEVCU+tNwBs9kE1CVObFkGZosA 2Utuz2UFsZkFJjNLvN/KCrJLWMBbYuVDe5Awr4CexLeXu9kgZl5nlJj5opERIiEocXLmExaI XnWJP/MuMYP0MgtISyz/xwERlpdo3jqbGcTmFAiUeLtoGeMERsFZSLpnIemehdA9C0n3AkaW VYySqQXFuem5xYYFRnmp5XrFibnFpXnpesn5uZsYwdGnpbWDcc+qD3qHGJk4GA8xSnAwK4nw in7oSRfiTUmsrEotyo8vKs1JLT7EKM3BoiTO++11b4qQQHpiSWp2ampBahFMlomDU6qB6UKv crw7V+mDv53zG/L3LJZuyMiafqN7J8fPW+f1Jla+X/VxLq/Kf3atZ4supCbWvlhWn7sj9fKx /BNzWb4Gft/e7eZl8ET6Uu5yo5CXiXfP6ry+/eNq5t7KzDBlz1c+/0J/qp2fLqGeFtbHcrvx JYsS77w5fV3/vn764cO8U3an4JSn5485PFvZrsO0smq+WPyFy+cONhsdF7E+FJ0bqXZ4ebXz AoEf0Uts3fa9/Oh6bt4j07l/V/1y45T898VFK8B3Xcb8hoeZH3d3TThY2vPfNUZgkubtslL+ 70prwroydh5ZUGnwLyhozsT99e8tGPxUdvL6BKXP4H/prZPn8S+hLk1vknqT6q8tbbtO/1Ji Kc5INNRiLipOBADQcTLALQMAAA== X-CMS-MailID: 20250122052858epcas2p4cac06ba9cd5db34cfd1e9b051a22f913 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----uRLjcQzjz6V5OP_3gESdNsGQj04rNmJgdrBpg7IReAZ1oX4H=_2b8e78_" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20250120083144epcas2p369584af764b617c3d2cb2a0568a45d6c References: <20250120083023.4162932-1-hyesoo.yu@samsung.com> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 4295940008 X-Stat-Signature: r16assp6yrxdtdrq5jeqxs6t7w8ufg1s X-Rspam-User: X-HE-Tag: 1737523742-154667 X-HE-Meta: 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 lrasjSof Z1VrZ1CArRtZ5EkF8d/8jjxSx+QLOMIX2cZSdxyyvBBllkiISbBoqNjaMoqLiO7XrV/YvZdMQz9j+30aMS3/0ay3ItODHbJlQumvypA6uHQog82ii34vnI34WSRHyT9L6d8GOKFtG7gF6QaK9fO50pj4Op2+6bGqzOnE5m1fkkmYSS7YHdDgYCMGM+bbxL9qWrMXk6xX+I/K8mM+Hs2X2tkbe4EO+472oDfIitFyofcOujziK3jtvibB4k2I2gRItHnA7+RvCVi6v7M8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: ------uRLjcQzjz6V5OP_3gESdNsGQj04rNmJgdrBpg7IReAZ1oX4H=_2b8e78_ Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Content-Disposition: inline On Tue, Jan 21, 2025 at 10:35:58PM +0900, Hyeonggon Yoo wrote: > On Mon, Jan 20, 2025 at 5:31 PM Hyesoo Yu wrote: > > Let's add Chengming, the author of the commit, to Cc, > as he might have some opinions about it. > > > Previously, the restore occured after printing the object in slub. > > After commit 47d911b ("slab: make check_object() more consistent"), > > at least 12 characters of the commit hash should be used to refer to a commit. > Documentation/process/submitting-patches.rst states that: > You should also be sure to use at least the first twelve > characters of the SHA-1 ID. > The kernel repository holds a lot of objects, making collisions > with shorter IDs a real > possibility. Bear in mind that, even if there is no collision with > your six-character ID > now, that condition may change five years from now. > Thanks for pointing out the mistake. > > the bytes are printed after the restore. This information about the bytes > > before the restore is highly valuable for debugging purpose. > > For instance, in a event of cache issue, it displays byte patterns > > by breaking them down into 64-bytes units. Without this information, > > we can only speculate on how it was broken. Hence the corrupted regions > > are printed prior to the restoration process. > > Probably this should be considered for -stable releases. What do you think? > [1] https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html > Thank you for the advice. I will add Cc:stable@vger.kernel.org in the next version. > > diff --git a/mm/slub.c b/mm/slub.c > > index c2151c9fee22..48cefc969480 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -1207,6 +1207,7 @@ check_bytes_and_report(struct kmem_cache *s, struct slab *slab, > > fault[0], value); > > > > skip_bug_print: > > + print_section(KERN_ERR, "Corrupt ", fault, end - fault); > > I don't think it's supposed to report an error here, per the name of > the label "skip_bug_print". > It is good point. I will move print_section above the skip_bug_print label. > Maybe move print_trailer() and add_taint() back to > check_bytes_and_report(), and report an error > only once and skip reporting if it's already reported? > > Best, > Hyeonggon > By passing a new parameter to the check_bytes_and_report(), It could be implemented. Would it be better to add a new boolean parameter to that function ? Or do you have any other ideas ? Thanks, Hyesoo. > > restore_bytes(s, what, value, fault, end); > > return 0; > > } > > -- > > 2.48.0 > > > ------uRLjcQzjz6V5OP_3gESdNsGQj04rNmJgdrBpg7IReAZ1oX4H=_2b8e78_ Content-Type: text/plain; charset="utf-8" ------uRLjcQzjz6V5OP_3gESdNsGQj04rNmJgdrBpg7IReAZ1oX4H=_2b8e78_--