From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E28443B961D; Wed, 25 Feb 2026 16:25:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772036746; cv=none; b=YynkNkDVHV/naB7Gs1pmDe0jMkB8xgZIyczg3SKik5g6ecs9p/tgxJlIe+QLOE03Wjwrs3kTOu0ub+3K9rDRDwTE7m+JNi2ZX4DtHgaQ/KkDbfmrlh17lCl43pOhnRWcuu6zgOWHfBYegh88jQ4ZOMLHZcixeGjz+g8w3R4n+S4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772036746; c=relaxed/simple; bh=guCbsIDgg8ayG9mMMymVvi9nZm4Jxc5WYXcp2FwHotE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Izqzrc7MnA8MwjhVb6uJm7nNY9g5oRGySLnzXsXWMDKw/tMdL4N1K3Kn4tQrVSDvSF+cXbD75SgkxQqJLvwfydnmzgysr3dvo+S5XEfI8KlluHr+KUQFPW2CLCPY3KMgcLb6CfngFshbyta0UoQfJ/wOXd2jWf79rfDscW5kBpE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cULZ5qEP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cULZ5qEP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3776DC116D0; Wed, 25 Feb 2026 16:25:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772036745; bh=guCbsIDgg8ayG9mMMymVvi9nZm4Jxc5WYXcp2FwHotE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cULZ5qEPz3eS7I+Fsxr6miX8AP+0kVboSS3w9recg6hIWBQu8d492aJMKFAtePr5C Yxw6zeIYl0NzkVTqOY+rZ3drD+EwjqMadIeU3+bhyJFoPCMVo0RZaVEqrkGtGCEwa4 bcriv7DhH2j0T9uGVeVdL+y8N8zL0iY2hVFSWAbADuMDI7VU71xE8IuqKkYJ+gZCsQ xR3OY+ov4QmLACxJ9gpX2X8RBJq46iAC34jhNq6rOPIAXeo23p3YGZbABHQNK9QxkC B70PkGx9oFgxrBgyJwJJ0C90f4GZTWG9hD7VkXOtmEBOVrFFkcSQg/ezo7Ywq0Uean YvcAIzi1k5CAg== Date: Wed, 25 Feb 2026 18:25:24 +0200 From: Mike Rapoport To: Ritesh Harjani Cc: Andrew Morton , Alex Shi , Alexander Gordeev , Andreas Larsson , Borislav Petkov , Brian Cain , "Christophe Leroy (CS GROUP)" , Catalin Marinas , "David S. Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Heiko Carstens , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , Jonathan Corbet , Klara Modin , "Liam R. Howlett" , Lorenzo Stoakes , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Muchun Song , Oscar Salvador , Palmer Dabbelt , Pratyush Yadav , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vineet Gupta , Vlastimil Babka , Will Deacon , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-cxl@vger.kernel.org, linux-doc@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org Subject: Re: [PATCH v3 24/29] arch, mm: consolidate initialization of SPARSE memory model Message-ID: References: <20260111082105.290734-1-rppt@kernel.org> <20260111082105.290734-25-rppt@kernel.org> <87tsv5h544.ritesh.list@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87tsv5h544.ritesh.list@gmail.com> Hello Ritesh, On Wed, Feb 25, 2026 at 09:00:35AM +0530, Ritesh Harjani wrote: > Mike Rapoport writes: > > > From: "Mike Rapoport (Microsoft)" > > > > Every architecture calls sparse_init() during setup_arch() although the > > data structures created by sparse_init() are not used until the > > initialization of the core MM. > > > > Beside the code duplication, calling sparse_init() from architecture > > specific code causes ordering differences of vmemmap and HVO initialization > > on different architectures. > > > > Move the call to sparse_init() from architecture specific code to > > free_area_init() to ensure that vmemmap and HVO initialization order is > > always the same. > > > > Hello Mike, > > [ 0.000000][ T0] ------------[ cut here ]------------ > [ 0.000000][ T0] WARNING: arch/powerpc/include/asm/io.h:879 at virt_to_phys+0x44/0x1b8, CPU#0: swapper/0 > [ 0.000000][ T0] Modules linked in: > [ 0.000000][ T0] CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.19.0-12139-gc57b1c00145a #31 PREEMPT > [ 0.000000][ T0] Hardware name: IBM pSeries (emulated by qemu) POWER10 (architected) 0x801200 0xf000006 of:SLOF,git-ee03ae pSeries > [ 0.000000][ T0] NIP: c000000000601584 LR: c000000004075de4 CTR: c000000000601548 > [ 0.000000][ T0] REGS: c000000004d1f870 TRAP: 0700 Not tainted (6.19.0-12139-gc57b1c00145a) > [ 0.000000][ T0] MSR: 8000000000021033 CR: 48022448 XER: 20040000 > [ 0.000000][ T0] CFAR: c0000000006016c4 IRQMASK: 1 > [ 0.000000][ T0] GPR00: c000000004075dd4 c000000004d1fb10 c00000000304bb00 c000000180000000 > [ 0.000000][ T0] GPR04: 0000000000000009 0000000000000009 c000000004ec94a0 0000000000000000 > [ 0.000000][ T0] GPR08: 0000000000018000 0000000000000001 c000000004921280 0000000048022448 > [ 0.000000][ T0] GPR12: c000000000601548 c000000004fe0000 0000000000000004 0000000000000004 > [ 0.000000][ T0] GPR16: 000000000287fb08 0000000000000060 0000000000000002 0000000002831750 > [ 0.000000][ T0] GPR20: 0000000002831778 fffffffffffffffd c000000004d78050 00000000051cbb00 > [ 0.000000][ T0] GPR24: 0000000005a40008 c000000000000000 c000000000400000 0000000000000100 > [ 0.000000][ T0] GPR28: c000000004d78050 0000000000000000 c000000004ecd4a8 0000000000000001 > [ 0.000000][ T0] NIP [c000000000601584] virt_to_phys+0x44/0x1b8 > [ 0.000000][ T0] LR [c000000004075de4] alloc_bootmem+0x144/0x1a8 > [ 0.000000][ T0] Call Trace: > [ 0.000000][ T0] [c000000004d1fb50] [c000000004075dd4] alloc_bootmem+0x134/0x1a8 > [ 0.000000][ T0] [c000000004d1fba0] [c000000004075fac] __alloc_bootmem_huge_page+0x164/0x230 > [ 0.000000][ T0] [c000000004d1fbe0] [c000000004030bc4] alloc_bootmem_huge_page+0x44/0x138 > [ 0.000000][ T0] [c000000004d1fc10] [c000000004076e48] hugetlb_hstate_alloc_pages+0x350/0x5ac > [ 0.000000][ T0] [c000000004d1fd30] [c0000000040782f0] hugetlb_bootmem_alloc+0x15c/0x19c > [ 0.000000][ T0] [c000000004d1fd70] [c00000000406d7b4] mm_core_init_early+0x7c/0xdf4 > [ 0.000000][ T0] [c000000004d1ff30] [c000000004011d84] start_kernel+0xac/0xc58 > [ 0.000000][ T0] [c000000004d1ffe0] [c00000000000e99c] start_here_common+0x1c/0x20 > [ 0.000000][ T0] Code: 6129ffff 792907c6 6529ffff 6129ffff 7c234840 40810018 3d2201e8 3929a7a8 e9290000 7c291840 41810044 3be00001 <0b1f0000> 3d20bfff 6129ffff 792907c6 > > > I think this is happening because, now in mm_core_early_init(), the > order of initialization between hugetlb_bootmem_alloc() and > free_area_init() is reversed. Since free_area_init() -> sparse_init() > is responsible for setting SECTIONS and vmemmap area. > > Then in alloc_bootmem() (from hugetlb_bootmem_alloc() path), it uses virt_to_phys(m)... > > /* > * For pre-HVO to work correctly, pages need to be on > * the list for the node they were actually allocated > * from. That node may be different in the case of > * fallback by memblock_alloc_try_nid_raw. So, > * extract the actual node first. > */ > if (m) > listnode = early_pfn_to_nid(PHYS_PFN(virt_to_phys(m))); > > > ... virt_to_phys on powerpc uses: > > static inline unsigned long virt_to_phys(const volatile void * address) > { > WARN_ON(IS_ENABLED(CONFIG_DEBUG_VIRTUAL) && !virt_addr_valid(address)); > > return __pa((unsigned long)address); > } > > #define virt_addr_valid(vaddr) ({ \ > unsigned long _addr = (unsigned long)vaddr; \ > _addr >= PAGE_OFFSET && _addr < (unsigned long)high_memory && \ > pfn_valid(virt_to_pfn((void *)_addr)); \ > }) > > > I think the above warning in dmesg gets printed from above WARN_ON, i.e. > because pfn_valid() is false, since we haven't done sparse_init() yet. Yes, I agree. > So, what I wanted to check was - do you think instead of virt_to_phys(), we > could directly use __pa() here() in mm/hugetlb.c, since these are > memblock alloc addresses? i.e.: > > // alloc_bootmem(): > - listnode = early_pfn_to_nid(PHYS_PFN(virt_to_phys(m))); > + listnode = early_pfn_to_nid(PHYS_PFN(__pa(m))); > > // __alloc_bootmem_huge_page(): > - memblock_reserved_mark_noinit(virt_to_phys((void *)m + PAGE_SIZE), > + memblock_reserved_mark_noinit(__pa((void *)m + PAGE_SIZE), It surely will work for powerpc :) I checked the definitions of __pa() on other architectures and it seems the safest and the easiest way to fix this. Would you send a formal patch? > Thoughts? > > -ritesh -- Sincerely yours, Mike.