From 34dc45be4563f344d59ba0428416d0d265aa4f4d Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Thu, 25 Feb 2021 17:17:08 -0800 Subject: mm: fix memory_failure() handling of dax-namespace metadata Given 'struct dev_pagemap' spans both data pages and metadata pages be careful to consult the altmap if present to delineate metadata. In fact the pfn_first() helper already identifies the first valid data pfn, so export that helper for other code paths via pgmap_pfn_valid(). Other usage of get_dev_pagemap() are not a concern because those are operating on known data pfns having been looked up by get_user_pages(). I.e. metadata pfns are never user mapped. Link: https://lkml.kernel.org/r/161058501758.1840162.4239831989762604527.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 6100e34b2526 ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages") Signed-off-by: Dan Williams Reported-by: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Naoya Horiguchi Cc: Michal Hocko Cc: Oscar Salvador Cc: Qian Cai Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory-failure.c | 6 ++++++ mm/memremap.c | 15 +++++++++++++++ 2 files changed, 21 insertions(+) (limited to 'mm') diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 55c671904aac..24210c9bd843 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1312,6 +1312,12 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, */ put_page(page); + /* device metadata space is not recoverable */ + if (!pgmap_pfn_valid(pgmap, pfn)) { + rc = -ENXIO; + goto out; + } + /* * Prevent the inode from being freed while we are interrogating * the address_space, typically this would be handled by diff --git a/mm/memremap.c b/mm/memremap.c index 16b2fb482da1..2455bac89506 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -80,6 +80,21 @@ static unsigned long pfn_first(struct dev_pagemap *pgmap, int range_id) return pfn + vmem_altmap_offset(pgmap_altmap(pgmap)); } +bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) +{ + int i; + + for (i = 0; i < pgmap->nr_range; i++) { + struct range *range = &pgmap->ranges[i]; + + if (pfn >= PHYS_PFN(range->start) && + pfn <= PHYS_PFN(range->end)) + return pfn >= pfn_first(pgmap, i); + } + + return false; +} + static unsigned long pfn_end(struct dev_pagemap *pgmap, int range_id) { const struct range *range = &pgmap->ranges[range_id]; -- cgit v1.2.3-70-g09d2