Commit 4627d76d authored Apr 01, 2020 by Wei Yang Committed by Linus Torvalds Apr 02, 2020

mm/sparsemem: get address to page struct instead of address to pfn



memmap should be the address to page struct instead of address to pfn.

As mentioned by David, if system memory and devmem sit within a section,
the mismatch address would lead kdump to dump unexpected memory.

Since sub-section only works for SPARSEMEM_VMEMMAP, pfn_to_page() is valid
to get the page struct address at this point.

Fixes: ba72b4c8 ("mm/sparsemem: support sub-section hotplug")
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Baoquan He <bhe@redhat.com>
Link: http://lkml.kernel.org/r/20200210005048.10437-1-richardw.yang@linux.intel.com


Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0c28759e

mm/sparse.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -894,7 +894,7 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn,

		/* Align memmap to section boundary in the subsection case */
		if (section_nr_to_pfn(section_nr) != start_pfn)
		memmap = pfn_to_kaddr(section_nr_to_pfn(section_nr));
		memmap = pfn_to_page(section_nr_to_pfn(section_nr));
		sparse_init_one_section(ms, section_nr, memmap, ms->usage, 0);

		return 0;

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