Messages in this thread Patch in this message | | | From | Wei Yang <> | Subject | [Patch v2] mm/sparsemem: get address to page struct instead of address to pfn | Date | Mon, 10 Feb 2020 08:50:48 +0800 |
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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: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug") Signed-off-by: Wei Yang <richardw.yang@linux.intel.com> CC: Dan Williams <dan.j.williams@intel.com> CC: David Hildenbrand <david@redhat.com> CC: Baoquan He <bhe@redhat.com>
--- v2: * adjust comment to mention the mismatch data would affect kdump
--- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/sparse.c b/mm/sparse.c index 586d85662978..4862ec2cfbc0 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -887,7 +887,7 @@ 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; -- 2.17.1
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