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 B1BA4C88E75 for ; Fri, 18 Sep 2026 07:03:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B7AEB6B0099; Fri, 18 Sep 2026 03:03:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B2BF06B009B; Fri, 18 Sep 2026 03:03:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A1B416B009D; Fri, 18 Sep 2026 03:03:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 732926B0099 for ; Fri, 18 Sep 2026 03:03:37 -0400 (EDT) Received: from smtpin30.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id DC216C0572 for ; Fri, 18 Sep 2026 07:03:36 +0000 (UTC) X-FDA: 85225992432.30.6BB2393 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf20.hostedemail.com (Postfix) with ESMTP id 4B1801C000B for ; Fri, 18 Sep 2026 07:03:34 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=aPqXv2uZ; spf=pass (imf20.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789715014; b=MP+FLqDdqZyVQhoSG/tPhAG47DO+DET1+Rd0eU0MvXb8jknZ+uer9YMX70G2A0Zh18zgf/ vqSYcai6jMnYcQPnDgN+ED6sCUDFuAzTCHpE5bBy2eNIy1DDf0IG4T2e43I8C57erEpIkr WghZDARKwCObT7kngOtPXA+PbM4y+l0= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=aPqXv2uZ; spf=pass (imf20.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@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=1789715014; 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=Ep+W+Lzk1KLKOXlBALTloOl7Wm88/geYoc+t7Jo7KS4=; b=JvWupNky++RytfrI6U1XDor8hlOx0MXUs+mTaR6sqbSdk4jfgrXt0vJ3SmyuJy7k/BLabY OiuW+BRWVOBGB9kTOOgFSAZw6r+xDeEe0RpcRS8TUPmSSsX2UvW7rh3jnfxA+lmJkl2OPe beXRs3m/TNEBrTYyNKA8tYzGOVGl6mg= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id D0CC160A5A; Fri, 18 Sep 2026 07:03:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4649D1F000FF; Fri, 18 Sep 2026 07:03:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789715013; bh=Ep+W+Lzk1KLKOXlBALTloOl7Wm88/geYoc+t7Jo7KS4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=aPqXv2uZx1vrO+PGIvxXetVU48iXAfQOmpEtCVU//nGS7ei6IPcEoDCJgz3uBJ/PI 4Ddj/QUegJf2lBmSwpiwGp0foLgSapfWj8m4hF+/C7TOHKXoy5QC/HRyVZE7XtGvDi oIiMOu5mX7bOS9af9DCTeeRRRfgZJHWVSCoGTm7NkbtqJVjEutnRc8rJ79LAAI6xNM LI35wyNgzvc0HS0XFS9SL1xqlGnKNh9JkTPxSK1Fbgm6sfte18euCfzErieKv0gAFR 1uDxAjt1ilWU3dgH+v91xGigckxp1MSaaqBJ4RgpW3b9zxO7GZ/pOARkUq7rmhnxBg 2S0VaeUw3vPyw== Date: Fri, 18 Sep 2026 10:03:22 +0300 From: Mike Rapoport To: Wandun Cc: catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, robh@kernel.org, saravanak@kernel.org, akpm@linux-foundation.org, baoquan.he@linux.dev, pasha.tatashin@soleen.com, pratyush@kernel.org, m.szyprowski@samsung.com, mark.rutland@arm.com, kernel@xen0n.name, alex@ghiti.fr, hpa@zytor.com, ruirui.yang@linux.dev, robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, iommu@lists.linux.dev Subject: Re: [PATCH v6 00/10] kdump: reduce vmcore size and capture time Message-ID: References: <20260902073116.802752-1-chenwandun1@gmail.com> <13cfcd99-e420-478b-8ce8-06674727977d@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <13cfcd99-e420-478b-8ce8-06674727977d@gmail.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 4B1801C000B X-Stat-Signature: qg4m86nufx9owjbzwc1d7unh7n4ww4i6 X-HE-Tag: 1789715014-621905 X-HE-Meta: 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 JGDhskOz bbKFgyW/T2vOrjWm/ZjGavnwWINGv84iNO4oyoYx32K2rNRFSEruJjrIS8g4eulpqx+rUl6PXF1bW9Qh27W4z4QklrBbRRaSszj7zIkW5YAhb1Cl4YxpY5XWRJZuxNFRU4qR9Wl+1KnCSRptBHJxzjcmBVcfqWxRmgOa8zF6LL/80qTqoMu4LwEr8V+Y2XHbLWCvmyfqfSIYMWHCHCQnT3mjdu16XdtN6mzHqtF0E9RcxFy5f6F5SMLntDJ/1VVtPSsWyI1YXPwpyKWrytlw/9LRzVh3VyWcr8dKFn3ajyFksrNUITIqAX4IZXTkZWHYgan1ZuKA2zyJax8sB+yVzkSS4uPPWVdNsACYkS0uANdHJSEw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi, On Tue, Sep 15, 2026 at 09:01:07PM +0800, Wandun wrote: > On 9/2/26 15:31, Wandun Chen wrote: > > From: Wandun Chen > > > > On SoCs that carve out large firmware-owned reserved memory (GPU, > > camera ISP, ...), kdump currently dumps those carveouts as part of > > system RAM even though their contents are firmware state that is not > > useful for kernel crash analysis. > > > > This series introduces a MEMBLOCK_NODUMP flag in memblock to filter > > reserved memory on DT-based architectures (arm64, riscv, loongarch). > > Reserved regions default are marked MEMBLOCK_NODUMP so kdump omits them; > > reusable CMA regions are different because their pages are handed back > > to the buddy allocator and may carry crash-relevant data. > > > > ACPI systems already filter reserved memory out of the vmcore through > > their existing path; only DT-based systems currently fail to filter these > > regions, which is what this series addresses. The flag lives in memblock > > itself rather than in a DT-only structure, so the mechanism is generic and > > both ACPI and DT systems can benefit from it (suggested by Rob, thanks) [1]. > > > > Since the reserved memory regions are filtered out, the vmcore is > > smaller in size and faster to produce. > > > > The series is based on linux-next and is organized as follows: > > > > Patches 1-4: Preparation and bugfixes: fix the missing HugeTLB > > flagname, switch riscv crash_mem to memblock, fold the > > duplicated per-arch memblock walks into the weak > > defaults, and serialize crash header preparation against > > memory hotplug. > > Patches 5-9: NODUMP infrastructure: switch crash_core to > > for_each_mem_region(), introduce the MEMBLOCK_NODUMP > > flag, add a dumpable flag to struct reserved_mem, and > > mark /reserved-memory and /memreserve/ entries with > > MEMBLOCK_NODUMP flag. > > Patch 10: Exclude MEMBLOCK_NODUMP regions from the vmcore ELF > > header. > > Hi, > > Gentle ping on the remaining patches of this series. > Patches 1, 7, 8 and 9 have been reviewed (thanks Mike and Marek); > Still looking for review on patches 2-6 and 10. I'm waiting for reviews from Baoquan and Dave for crash core patches before applying this series. > Would appreciate a look when you have a moment, happy to rework > anything based on feedback. > > Best regards, > Wanun > > > > > In v5, Sashiko found some pre-existing issues related to reserved-memory, > > and has no dependency on this series, so these issues have been addressed > > in a separate series [2]. > > > > v5 --> v6: > > 1. Serialize crash header preparation against memory hotplug to avoid > > out-of-bounds or use-after-free issues. > > > > 2. MEMBLOCK_NODUMP marking is now done after memblock allows resizing, > > avoiding a panic from too few regions before resize is permitted. > > > > 3. Reordered the patches, put pre-existing bugfixes earlier in the series. > > > > > > v4 --> v5: > > 1. Rework the mechanism around a memblock-level MEMBLOCK_NODUMP flag > > (suggested by Rob) instead of the v4 opt-in 'dumpable' flag on > > DT-only struct reserved_mem. > > 2. Switch the riscv vmcore elf header preparation to use memblock > > instead of the resource tree, aligning it with arm64 and loongarch, > > so riscv also can exclude reserved memory from vmcore. > > 3. Deduplicate the vmcore elf header preparation: arm64, riscv and > > loongarch open-coded the same logic, so fold it into shared > > __weak defaults in crash_core. > > 4. Drop the v4 patch that saved /memreserve/ entries into the > > reserved_mem array; /memreserve/ is now marked MEMBLOCK_NODUMP > > directly. > > > > v3 --> v4: > > 1. Rebase this series on v7.2-rc1. > > 2. Add two cleanup patches (patch 02/03). > > 3. Simplify patch 03 to avoid checking whether initial_boot_params is > > NULL multiple times, suggested by Rob. > > > > v2 --> v3: > > 1. Fix out-of-bounds issue if device tree lacks /reserved-memory node. > > 2. Fix UAF issue when alloc_reserved_mem_array() fails. > > 3. Add some prepare patches. > > > > v1 --> v2: > > 1. v1 added an opt-out DT property ('linux,no-dump'). Per Rob's > > feedback [3], v2 drop that property and exclude reserve memory > > by default. > > 2. Split some prepared patches from the original patches. > > 3. Address coding-style comments on patch 5 from Rob. > > > > [1] https://lore.kernel.org/lkml/20260723234126.GA3253409-robh@kernel.org/ > > [2] https://lore.kernel.org/lkml/20260818092420.2859026-1-chenwandun1@gmail.com/ > > [3] https://lore.kernel.org/lkml/20260506144542.GA2072596-robh@kernel.org/ > > > > Meijing Zhao (1): > > mm: memblock: add missing HugeTLB flag name > > > > Wandun Chen (9): > > riscv: build crash_mem ranges from memblock instead of resource tree > > crash_core: fold duplicated memblock arch hooks into the weak default > > crash_core: serialize crash header preparation against hotplug > > crash_core: replace for_each_mem_range() with for_each_mem_region() > > memblock: introduce MEMBLOCK_NODUMP flag > > of: reserved_mem: add dumpable flag to opt-in vmcore > > of: reserved_mem: mark /reserved-memory entries with MEMBLOCK_NODUMP > > of: reserved_mem: mark /memreserve/ entries as MEMBLOCK_NODUMP > > crash_core: skip MEMBLOCK_NODUMP regions when building vmcore ELF > > header > > > > arch/arm64/kernel/machine_kexec_file.c | 29 ------------ > > arch/loongarch/kernel/machine_kexec_file.c | 27 ------------ > > arch/riscv/Kconfig | 2 +- > > arch/riscv/kernel/machine_kexec_file.c | 33 -------------- > > arch/x86/kernel/crash.c | 2 +- > > drivers/of/fdt.c | 2 + > > drivers/of/of_private.h | 2 + > > drivers/of/of_reserved_mem.c | 48 ++++++++++++++++++++ > > include/linux/crash_core.h | 2 + > > include/linux/memblock.h | 9 ++++ > > include/linux/of_reserved_mem.h | 1 + > > kernel/crash_core.c | 51 ++++++++++++++++++++-- > > kernel/dma/contiguous.c | 1 + > > mm/memblock.c | 17 ++++++++ > > 14 files changed, 131 insertions(+), 95 deletions(-) > > > > -- Sincerely yours, Mike.