mirror of
https://github.com/linux-msm/laptops-kernel.git
synced 2026-08-13 14:19:53 -07:00
Hui ZhuandAndrew Morton
67a06fdfbf
KCSAN reports a data race between page_to_nid()/folio_pgdat() reading page->flags and folio_trylock()/folio_lock() concurrently doing test_and_set_bit_lock(PG_locked, ...) on the same word, e.g.: BUG: KCSAN: data-race in __lruvec_stat_mod_folio / shmem_get_folio_gfp The race is benign: nid/zone bits are set once at page init and never overlap with PG_locked. However, ASSERT_EXCLUSIVE_BITS() inside memdesc_nid/zonenum() was checking a by-value copy of the flags word, not the live page->flags, so it failed to annotate the real access. Change memdesc_nid(), memdesc_zonenum(), memdesc_section(), and memdesc_is_zone_device() to take a const memdesc_flags_t * and update all callers to pass &page->flags / &folio->flags, so ASSERT_EXCLUSIVE_BITS() operates on the actual shared word. Guard the ASSERT_EXCLUSIVE_BITS() call in memdesc_zonenum() under ZONES_WIDTH != 0 to avoid a zero-mask check on configs where the zone field is absent. memdesc_section() needs no such guard, since SECTIONS_WIDTH is never 0 wherever SECTION_IN_PAGE_FLAGS is defined. Under CONFIG_NUMA=n, memdesc_nid() itself is stubbed to "return 0" instead of reading page->flags, since NODES_MASK is 0 and the check can never fire; page_to_nid()/folio_nid() now just call memdesc_nid() unconditionally and rely on that stub, instead of duplicating the CONFIG_NUMA split at each call site. [zhuhui@kylinos.cn: v11] Link: https://lore.kernel.org/20260708083308.747930-1-hui.zhu@linux.dev [ziy@nvidia.com: build fix] Link: https://lore.kernel.org/DJSGLP9VFLRI.355AAWR2VHIEL@nvidia.com Link: https://lore.kernel.org/20260630070810.470763-1-hui.zhu@linux.dev Signed-off-by: Hui Zhu <zhuhui@kylinos.cn> Co-developed-by: David Hildenbrand (Arm) <david@kernel.org> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Barry Song <baohua@kernel.org> Cc: Kairui Song <kasong@tencent.com> Cc: Liam R. Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Cc: Wei Xu <weixugc@google.com> Cc: Yuanchu Xie <yuanchu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_MEMORY_MODEL_H
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#define __ASM_MEMORY_MODEL_H
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#include <linux/pfn.h>
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#ifndef __ASSEMBLER__
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/*
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* supports 3 memory models.
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*/
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#if defined(CONFIG_FLATMEM)
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#ifndef ARCH_PFN_OFFSET
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#define ARCH_PFN_OFFSET (0UL)
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#endif
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#define __pfn_to_page(pfn) (mem_map + ((pfn) - ARCH_PFN_OFFSET))
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#define __page_to_pfn(page) ((unsigned long)((page) - mem_map) + \
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ARCH_PFN_OFFSET)
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/* avoid <linux/mm.h> include hell */
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extern unsigned long max_mapnr;
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#ifndef pfn_valid
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static inline int pfn_valid(unsigned long pfn)
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{
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unsigned long pfn_offset = ARCH_PFN_OFFSET;
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return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
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}
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#define pfn_valid pfn_valid
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#ifndef for_each_valid_pfn
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#define for_each_valid_pfn(pfn, start_pfn, end_pfn) \
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for ((pfn) = max_t(unsigned long, (start_pfn), ARCH_PFN_OFFSET); \
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(pfn) < min_t(unsigned long, (end_pfn), \
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ARCH_PFN_OFFSET + max_mapnr); \
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(pfn)++)
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#endif /* for_each_valid_pfn */
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#endif /* valid_pfn */
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#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
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/* memmap is virtually contiguous. */
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#define __pfn_to_page(pfn) (vmemmap + (pfn))
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#define __page_to_pfn(page) (unsigned long)((page) - vmemmap)
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#elif defined(CONFIG_SPARSEMEM)
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/*
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* Note: section's mem_map is encoded to reflect its start_pfn.
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* section[i].section_mem_map == mem_map's address - start_pfn;
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*/
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#define __page_to_pfn(pg) \
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({ const struct page *__pg = (pg); \
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int __sec = memdesc_section(&__pg->flags); \
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(unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
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})
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#define __pfn_to_page(pfn) \
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({ unsigned long __pfn = (pfn); \
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struct mem_section *__sec = __pfn_to_section(__pfn); \
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__section_mem_map_addr(__sec) + __pfn; \
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})
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#endif /* CONFIG_FLATMEM/SPARSEMEM */
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/*
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* Convert a physical address to a Page Frame Number and back
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*/
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#define __phys_to_pfn(paddr) PHYS_PFN(paddr)
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#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
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#define page_to_pfn __page_to_pfn
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#define pfn_to_page __pfn_to_page
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#ifdef CONFIG_DEBUG_VIRTUAL
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#define page_to_phys(page) \
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({ \
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unsigned long __pfn = page_to_pfn(page); \
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\
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WARN_ON_ONCE(!pfn_valid(__pfn)); \
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PFN_PHYS(__pfn); \
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})
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#else
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#define page_to_phys(page) PFN_PHYS(page_to_pfn(page))
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#endif /* CONFIG_DEBUG_VIRTUAL */
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#define phys_to_page(phys) pfn_to_page(PHYS_PFN(phys))
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#endif /* __ASSEMBLER__ */
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#endif
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