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Fri, 18 Sep 2026 07:31:05 +0000 X-Mizu-Trace-ID: 33707ef04d706312 X-Migadu-Flow: FLOW_OUT Date: Fri, 18 Sep 2026 15:31:00 +0800 From: Baoquan He To: Mike Rapoport Cc: Wandun , 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, 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: X-Rspam-User: X-Rspamd-Queue-Id: 2D4BA20007 X-Stat-Signature: ea8cch1bz18s7w44yodfzz93gx9fep3t X-Rspamd-Server: rspam01 X-HE-Tag: 1789716666-971971 X-HE-Meta: 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 H9zpdw2b 163cA/OTbWiIg1lcl0dV/adAtenZ9ouKplJ+OhIhPoW/5NspTEOTm6U8QOm77ZyKjAd07PqHBPkP9c6iktrnZ2VfbBOe9s8Njepql8hmwDtAuhEFUw8akS3qFXYN4xDBs7AnbbDerFP7ced+m7NIObYc+4KBiZS6iWsmMNLjaTDwaVmIwrXrwsvychbSMZLPM6SLnOBPDq/JICQH8c+NWBk+8Pv1CCypeJEI+3uKoHLbIxceOndo454o2snmc2ycn7p7HFtrlCkIwp5XX5oJynOAHrdF1E3R0M3sJFg2I7isXiaixvbwDhZwgNF+CBQ2mUAu5HIUoZA5A7GO6FST65w/S2DY8SJGN/HGbfSXqdJR77U0fF2RqkKYpeA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 09/18/26 at 10:03am, Mike Rapoport wrote: > 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 ...snip... > > > 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. I will go through the crash core patches, thanks for reminding. > > > 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.