Commit 12b2285b authored by Matthew Brost's avatar Matthew Brost Committed by Andrew Morton
Browse files

mm/zone_device: reinitialize large zone device private folios 

Reinitialize metadata for large zone device private folios in
zone_device_page_init prior to creating a higher-order zone device private
folio.  This step is necessary when the folio's order changes dynamically
between zone_device_page_init calls to avoid building a corrupt folio.  As
part of the metadata reinitialization, the dev_pagemap must be passed in
from the caller because the pgmap stored in the folio page may have been
overwritten with a compound head.

Without this fix, individual pages could have invalid pgmap fields and
flags (with PG_locked being notably problematic) due to prior different
order allocations, which can, and will, result in kernel crashes.

Link: https://lkml.kernel.org/r/20260116111325.1736137-2-francois.dugast@intel.com


Fixes: d245f9b4 ("mm/zone_device: support large zone device private folios")
Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Signed-off-by: default avatarFrancois Dugast <francois.dugast@intel.com>
Acked-by: default avatarFelix Kuehling <felix.kuehling@amd.com>
Reviewed-by: default avatarBalbir Singh <balbirs@nvidia.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cbbbf779

arch/powerpc/kvm/book3s_hv_uvmem.c

+1 −1
Original line number Diff line number Diff line
@@ -723,7 +723,7 @@ static struct page *kvmppc_uvmem_get_page(unsigned long gpa, struct kvm *kvm) 


	dpage = pfn_to_page(uvmem_pfn);

	dpage->zone_device_data = pvt;

	zone_device_page_init(dpage, 0);

	zone_device_page_init(dpage, &kvmppc_uvmem_pgmap, 0);

	return dpage;

out_clear:

	spin_lock(&kvmppc_uvmem_bitmap_lock);

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c

+1 −1
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn) 
	page = pfn_to_page(pfn);

	svm_range_bo_ref(prange->svm_bo);

	page->zone_device_data = prange->svm_bo;

	zone_device_page_init(page, 0);

	zone_device_page_init(page, page_pgmap(page), 0);

}



static void

drivers/gpu/drm/drm_pagemap.c

+1 −1
Original line number Diff line number Diff line
@@ -197,7 +197,7 @@ static void drm_pagemap_get_devmem_page(struct page *page, 
					struct drm_pagemap_zdd *zdd)

{

	page->zone_device_data = drm_pagemap_zdd_get(zdd);

	zone_device_page_init(page, 0);

	zone_device_page_init(page, page_pgmap(page), 0);

}



/**

drivers/gpu/drm/nouveau/nouveau_dmem.c

+1 −1
Original line number Diff line number Diff line
@@ -425,7 +425,7 @@ nouveau_dmem_page_alloc_locked(struct nouveau_drm *drm, bool is_large) 
			order = ilog2(DMEM_CHUNK_NPAGES);

	}



	zone_device_folio_init(folio, order);

	zone_device_folio_init(folio, page_pgmap(folio_page(folio, 0)), order);

	return page;

}

include/linux/memremap.h

+6 −3
Original line number Diff line number Diff line
@@ -224,7 +224,8 @@ static inline bool is_fsdax_page(const struct page *page) 
}



#ifdef CONFIG_ZONE_DEVICE

void zone_device_page_init(struct page *page, unsigned int order);

void zone_device_page_init(struct page *page, struct dev_pagemap *pgmap,

			   unsigned int order);

void *memremap_pages(struct dev_pagemap *pgmap, int nid);

void memunmap_pages(struct dev_pagemap *pgmap);

void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap);
@@ -234,9 +235,11 @@ bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn); 


unsigned long memremap_compat_align(void);



static inline void zone_device_folio_init(struct folio *folio, unsigned int order)

static inline void zone_device_folio_init(struct folio *folio,

					  struct dev_pagemap *pgmap,

					  unsigned int order)

{

	zone_device_page_init(&folio->page, order);

	zone_device_page_init(&folio->page, pgmap, order);

	if (order)

		folio_set_large_rmappable(folio);

}