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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 98EBEC982D2 for ; Fri, 18 Sep 2026 07:03:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Ep+W+Lzk1KLKOXlBALTloOl7Wm88/geYoc+t7Jo7KS4=; b=aXMHDZJF1WiFS4DsJ1Aj/F0gsi IJ9qmm38kBNVK84qWzwvCsO8u6euNEJp/bEudEXzVX9XbElTs9rMFZS0LNb5j0ar1/EcKsQtCGJHA 0M7AzseCVSK4tnLZH+YSRLUcO4/NfAE3I4sDu3fUcHq8iJLtsp+F5HgQxQyXX8YqcX2d8QbGcQhsz ZAw6GnP4u6yre7FqJLcsHit7pj2yqDmrk2N10t/eHHJpTBz2b3jtcdoWQjKFWbdQRz7TJ75M8EYZr 9T1oApANg0aYJC17CpP3iEhQH4mkhvIB9SUq6u6VZHUKqjRrZ9rUf0DZxfU1dKSVzhDjTgRCkiCn4 RXwreeGw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7SdD-0000000DdXr-3c4j; Fri, 18 Sep 2026 07:03:35 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x7SdC-0000000DdXd-3S0d; Fri, 18 Sep 2026 07:03:34 +0000 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-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org 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.