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Wed, 25 Feb 2026 01:34:14 -0800 (PST) Received: from dw-tp ([203.81.242.210]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3590188126esm2256635a91.6.2026.02.25.01.33.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Feb 2026 01:34:13 -0800 (PST) From: Ritesh Harjani (IBM) To: Mike Rapoport , Andrew Morton Cc: Alex Shi , Alexander Gordeev , Andreas Larsson , Borislav Petkov , Brian Cain , "Christophe Leroy (CS GROUP)" , Catalin Marinas , "David S. 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Re: [PATCH v3 24/29] arch, mm: consolidate initialization of SPARSE memory model In-Reply-To: <20260111082105.290734-25-rppt@kernel.org> Date: Wed, 25 Feb 2026 09:00:35 +0530 Message-ID: <87tsv5h544.ritesh.list@gmail.com> References: <20260111082105.290734-1-rppt@kernel.org> <20260111082105.290734-25-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260225_093417_699409_DF2EF7E5 X-CRM114-Status: GOOD ( 17.83 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org 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. 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), Thoughts? -ritesh