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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7F463CA5FA2 for ; Mon, 28 Sep 2026 17:36:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7D6B16B0088; Mon, 28 Sep 2026 13:36:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 786BD6B008C; Mon, 28 Sep 2026 13:36:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 601686B00A9; Mon, 28 Sep 2026 13:36:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 32F366B0088 for ; Mon, 28 Sep 2026 13:36:43 -0400 (EDT) Received: from smtpin10.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id BBE9AA02B2 for ; Mon, 28 Sep 2026 17:36:42 +0000 (UTC) X-FDA: 85263875844.10.B3C5A8F Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf19.hostedemail.com (Postfix) with ESMTP id 299741A0007 for ; Mon, 28 Sep 2026 17:36:40 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=CdVMt+Fz; spf=pass (imf19.hostedemail.com: domain of sashiko-bot@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sashiko-bot@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790617001; h=from:from:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=xXafi02ZLO1Y0xc1WsCP1jTVPyy0rIJ0X6evEJWG+Cs=; b=JL6A0WR143UK6Fb9syHVu3Q0O2JekBP6GfD+S4KxN6pVO2VR3YsPq5pdLWQXhgce/VDav2 lQgFhkInRa6vjPLg6tpH2GT8QXLfesiEdgSuaRyqWYP9/HatGFA5Ale5PbgsyyGH/wEk7I XnCnMFu+hay/q+MyYS3780O8+gPkURU= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790617001; b=NGaJJVo41RF87GLAqidT3ZBjwKN9Hhj6Gimu4uXZRkUzRcvrb0QFUnjfRcTDMh0MG8XjyT G2NRhLuRDiCwAOjYg0f2PAG7rOGL54Owaed0PgB8bcWrOV2TW7K1f/NaykdnJpB9SCA0cu XXSmuO6m1dZUhHtm+uZAuDHJYbZkRw0= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=CdVMt+Fz; spf=pass (imf19.hostedemail.com: domain of sashiko-bot@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=sashiko-bot@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 88D0B60120; Mon, 28 Sep 2026 17:36:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78B211F000FF; Mon, 28 Sep 2026 17:36:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790617000; bh=xXafi02ZLO1Y0xc1WsCP1jTVPyy0rIJ0X6evEJWG+Cs=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=CdVMt+Fzf8G8t9rbknnGaVrM5SS+D6vf8+Yoh8W6ZNN6HA8AwFKbWq4iAqfZXz+Ft d6MVIyxwinfxhUDgeSbx7Dog/6xDVinP9/nnAQpm3L3BeHj6F2w9uLhGMX0RIwqRFp ow0hYfT1lH9zRieXdzWZTFJ3OuwSjepCBV16JWZsA0vXLvh1ZOhMNs5F+OsbJov4tp Rvcjcg0CXhk62W2ijvnpQb0dh5CrMyp0hQ+z20rlXdt1LlRtr6DDTzOnq5FPBrwN13 /j0jojUVX3IMJsrMgcEwhZ5ROe55Wv7PFan2FBHF9O9li/r2rx/qWmXuyEF8Ks1t22 NGObYvk9JQFvQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 02/12] lib, kexec: Add a secret pool for key material Reply-To: sashiko-reviews@lists.linux.dev To: "Rob Herring" , "Barry Song" , "Matthew Brost" , "Zi Yan" , "David Howells" , "Dev Jain" , "David Hildenbrand" , "Herbert Xu" , "Andrew Morton" , "Benjamin Marzinski" , "Michal Hocko" , "Johannes Weiner" , =?utf-8?b?SmFuIFNlYmFzdGlhbiBHw7Z0dGU=?= , "Mark Rutland" , "Kiryl Shutsemau" , "Catalin Marinas" , "James Morris" , "Rik van Riel" , "Usama Arif" , "Mikulas Patocka" , "Mike Snitzer" , "Lance Yang" , "Randy Dunlap" , "Baolin Wang" , "Byungchul Park" , "Paul Moore" , "Lorenzo Stoakes" , "Mike Rapoport" , "Liam R. Howlett" , "David S. Miller" , "Peter Xu" , "Jonathan Corbet" , "Brendan Jackman" , "Harry Yoo" , "Rafael J. Wysocki" , "Arnd Bergmann" , "Greg Kroah-Hartman" , "Oscar Salvador" , "Pedro Falcato" , "Gregory Price" , "Mimi Zohar" , "Saravana Kannan" , "Joshua Hahn" , "Baoquan He" , "Jann Horn" , "Serge E. Hallyn" , "Pasha Tatashin" , "Muchun Song" , "Suren Baghdasaryan" , "Shuah Khan" , "Alistair Popple" , "Jarkko Sakkinen" , "Ryan Roberts" , "Danilo Krummrich" , "James Bottomley" , "Vlastimil Babka" , "Alasdair Kergon" , "Will Deacon" , "Nico Pache" , "Pratyush Yadav" , "Dave Young" , "Ying Huang" Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, keyrings@vger.kernel.org, robh@kernel.org, linux-doc@vger.kernel.org, conor+dt@kernel.org, dm-devel@lists.linux.dev, linux-mm@kvack.org, linux-integrity@vger.kernel.org, devicetree@vger.kernel.org, driver-core@lists.linux.dev, linux-fsdevel@vger.kernel.org, "Eric Biggers" , linux-security-module@vger.kernel.org, linux-crypto@vger.kernel.org, linux-arch@vger.kernel.org In-Reply-To: <20260928-crash-memaction-upstream-20260921-v3-2-e511e9ee2329@jaseg.de> References: <20260928-crash-memaction-upstream-20260921-v3-0-e511e9ee2329@jaseg.de> <20260928-crash-memaction-upstream-20260921-v3-2-e511e9ee2329@jaseg.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 28 Sep 2026 17:36:35 +0000 Message-Id: <20260928173636.78B211F000FF@smtp.kernel.org> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 299741A0007 X-Stat-Signature: 3dmsbpphf1to4nyki8aeonqbsd6e1c9k X-Rspam-User: X-HE-Tag: 1790617000-270434 X-HE-Meta: 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 1Y9BN8pq kvrS5Uv2s+ifucCyxcodQ3aw+PEsi1zoFbSH7bD2xpik/yavwylZq2hYAd0gGWZnm9/k2rmOKTEHqdGXCJC/oPTVtYOVVJcrddAxKtc0fXutGDp6E/I/ldgdgFeViejbxYleA5JmdtgWORALz1POON+PRYO7NjkgTDCZU9NZ7RMp/qj9L8LUKwOIxSY6ypXd8K9A0dDFW4euYe+2BXDJCAVB6C+5mOFwpjQsRarUT+CJLKknw+VZUNgAB81taCeE4uKq29+IhZEOUkOcJVho7K9Zie2oTnnf7Gya4tegLhhM91aRFj0L9i2ahVKpgvPd5PXMYxl4W98NXexisS8hm+rL4MzGYYwvfZLwGgmfGX8s537TrsLjWRLApKZfoFaYr3eDjazeLMJ1ER2qULieBPeum9tgO93lVxGc3lPADiOy815IIlEXVPI8QblZPdZMIgpWvjDbFPGo7RjZaiL/PIMCpw49JS6kvHd8HNZJUbyr7vg8WRLTXEFN9n0ZydVts7zTzD0ti0CCQQ285uNYA4m+CJCFEv1eFKiKwHIh0rORzj3xlSWYvJHI0wmxJ5vS2wPlBo+Kk6X0BSyJJsbkhU+H/I0FF/cbsMi8o9kf4O53XytI9gKdbPJH3q1jY808mlgHF6b7K+oC6gInF0HfpILoX+dS+kZgPV6AmConzPho45bE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] lib/secret_pool: fallback to shared kmalloc inadvertently marks en= tire pages as secret -- commit 774a436bfd0576d919ce17b831096d5b8c8dbbb5 Author: Jan Sebastian G=C3=B6tte lib, kexec: Add a secret pool for key material =20 Key material allocated with kmalloc() shares its slab pages with unrelated allocations. crash_memaction marks memory at page granularity, so smaller objects in shared slab pages can't cleanly be marked or unmarked. This commit adds a secret pool built on kmem_buckets to hold such keys in marked pages. > diff --git a/lib/secret_pool.c b/lib/secret_pool.c > new file mode 100644 > index 0000000000000..62954847091a0 > --- /dev/null > +++ b/lib/secret_pool.c > @@ -0,0 +1,27 @@ [ ... ] > +void *secret_pool_alloc_node(size_t size, gfp_t flags, int node) > +{ > + void *p =3D kmem_buckets_alloc_node_track_caller(secret_pool, size, > + flags, node); > + > + crash_memaction_mark(p, size, CRASH_MEMACTION_SECRET); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ [Severity: High] Does this unconditionally mark the allocation even if it falls back to a sh= ared kmalloc page? The commit message notes that if the secret pool is used before its initcall runs or if pool creation fails, allocations will fall back to ordinary kmal= loc caches. Because crash_memaction_mark() operates at page granularity, wouldn't calli= ng it on a shared kmalloc page inadvertently mark the entire page (and unrelat= ed kernel objects sharing it) as a secret? In the event of a crash, could this cause the kdump kernel to wipe or exclu= de these shared pages, potentially destroying crash data? > + > + return p; > +} > +EXPORT_SYMBOL_GPL(secret_pool_alloc_node); --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260928-crash-mema= ction-upstream-20260921-v3-0-e511e9ee2329@jaseg.de?part=3D2