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b=Ga22zn7Znw2giwTWdZhF7ERP6ahnkXPahTQV30EGlt63rtJdEvi2AmaroAHKYFW3D AQKKLZeFMp7rGwGqhQxHeSde2OHEbrURkNw+yM+wdegu60hyTLDHh3sgSr/paQ00dW xlM5v53gRcBNgUjN+R3OTk/VzfmUAlH+ZJL4qKvPLKIEtEW3AixFRAowFKf2/uHtkq 4CuzPuSYx/2azw9fOuQsz5qjIulruGo6suk1Qfy6OTF/87YfLw83vkVTVR3Kd4qYFd SpNemZ8zeuzhrt7W5z0IGUoN88j1phJRIrPgxUs57AIsjA2GDifSbp0VUX11OLQR+B KSaktEDJ0R83Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH V4 4/4] arm64/mm: Use pgdp_get() for PGD accesses Reply-To: sashiko-reviews@lists.linux.dev To: "Anshuman Khandual" , catalin.marinas@arm.com, will@kernel.org Cc: "Ryan Roberts" , "Mark Rutland" , "Lorenzo Stoakes" , "Andrew Morton" , "David Hildenbrand" , "Mike Rapoport" , "Linu Cherian" , linux-mm@kvack.org, kasan-dev@googlegroups.com In-Reply-To: <20261105043403.3326445-5-anshuman.khandual@arm.com> References: <20261105043403.3326445-1-anshuman.khandual@arm.com> <20261105043403.3326445-5-anshuman.khandual@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 06 Nov 2026 04:34:47 +0000 X-Stat-Signature: fouzouccj3ea5eg3qynqy65mrbcypmey X-Rspamd-Server: rspam01 X-Rspam-User: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspamd-Queue-Id: 1E5541C0005 X-HE-Tag: 1793939688-962331 X-HE-Meta: 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 2Ls5rjXq 4qFEynD21uNQHRiouPS50Lb0vG366xtufPjA8pe0x35qmLtrXQ9SqnbFB7eb46RWK3T0GOiDWFuaAbMBKDeSlRl2ZKwulJNf4hADm94LlOrdwgSedIGd3kjqSoD3QBXOHsWmBuBssbce2NPcdlystSYKuUOFiM3vK8XMkTKSsc/D45A6asle+LRN613KaiqlSzY3wIst001wm25Q/diuxuseqh+gUQPceJWrGxjzQ+sLxCksl4LKK4ChBwdadwEayG3mnUgQfR9NNvNw/6xztA8dpvs7G5hox3LJZNijibKdPSu/YMOcxhkhx1hiBZsTnC55XiZYofbibyGym03gyGKuFp65XvVTq4lNsu/lrCgOl9sd+WNDplx+rDGFLp2N2QegK7URnymexoWkGG+7JwyQWSpthHIM4quHZJ4FtoIzXzDjESwseO6hMvPNinUyf7JzLSWN+svpQtEpc+ity+yPKnPavBswBlrGoDWRlJbKT3qLtrWgokmLRqJhQYvW+BDmM7KmoGT+dY2J+p80Q5sqmU9Tx/ZJcTehtIyxxVCKHQ/WQhjs9wqF1X6zR07KyF0SGsoEa/+hTDLbors2XidHQ7on1GlmnfGPkDiQor1CrXKyLVYN/OP9XRT8s0Ql2gTgdBEAtkZdQld8GZAGcNnVTxyTIpxzFy2uwUeuH54kKYnM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: Thank you for your contribution! Sashiko AI review found 1 potential issue(= s) to consider: - [High] arm64/mm: KASAN fault in p4d_offset_phys() during kasan_early_init= () -- commit e9bf68a7a555b3c58c2a0a8736f337dde8136ab9 Author: Anshuman Khandual arm64/mm: Use pgdp_get() for PGD accesses This commit replaces READ_ONCE() with pgdp_get() for PGD accesses and moves p4d_offset() and p4d_offset_phys() from arch/arm64/include/asm/pgtable.h into arch/arm64/mm/mmu.c to avoid header include dependencies. > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 5b5a85a0527d6..11015e1deb32f 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c [ ... ] > @@ -2463,3 +2463,17 @@ pud_t *pud_offset(p4d_t *p4dp, unsigned long addr) > return pud_offset_lockless(p4dp, p4dp_get(p4dp), addr); > } > #endif /* CONFIG_PGTABLE_LEVELS > 3 */ > + > +#if CONFIG_PGTABLE_LEVELS > 4 > +phys_addr_t p4d_offset_phys(pgd_t *pgdp, unsigned long addr) > +{ > + VM_WARN_ON_ONCE(!pgtable_l5_enabled()); > + > + return pgd_page_paddr(pgdp_get(pgdp)) + p4d_index(addr) * sizeof(p4d_t); > +} [Severity: High] Does moving p4d_offset_phys() (and pud_offset_phys() in the preceding patch) out-of-line into arch/arm64/mm/mmu.c cause a translation fault during early boot when KASAN is enabled with 5-level (or 4-level) page tables? During early boot, __primary_switched calls kasan_early_init() before the KASAN shadow region is mapped. Because any KASAN shadow check will fault until kasan_early_init() finishes populating the early shadow page tables, arch/arm64/mm/Makefile disables KASAN sanitization for kasan_init.o: KASAN_SANITIZE_kasan_init.o :=3D n and set_swapper_pgd() in arch/arm64/mm/mmu.c is marked noinstr for the same reason. When kasan_early_init() populates the shadow page tables, it calls into p4d_offset_phys() and pud_offset_phys(): kasan_early_init() kasan_pgd_populate(..., early=3Dtrue) kasan_p4d_populate(..., early=3Dtrue) kasan_p4d_offset(..., early=3Dtrue) p4d_offset_kimg() p4d_offset_phys() kasan_pud_populate(..., early=3Dtrue) kasan_pud_offset(..., early=3Dtrue) pud_offset_kimg() pud_offset_phys() Previously, p4d_offset_phys() and pud_offset_phys() were static inline functions in arch/arm64/include/asm/pgtable.h, so calls from kasan_init.c were inlined into kasan_init.o and compiled without KASAN instrumentation. Now that both functions live in arch/arm64/mm/mmu.c, which is KASAN-sanitiz= ed, the compiler emits KASAN shadow checks for their memory accesses (such as pgdp_get(pgdp), p4dp_get(p4dp), and vabits_actual) before the early shadow memory is mapped. Should p4d_offset_phys() and pud_offset_phys() be marked noinstr or __no_sanitize_address? --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261105043403.3326= 445-1-anshuman.khandual@arm.com?part=3D4