The patch titled Subject: mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2 has been added to the -mm tree. Its filename is mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-sparse-fix-kernel-crash-with-pfn... and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-sparse-fix-kernel-crash-with-pfn...

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------------------------------------------------------ From: "Aneesh Kumar K.V" aneesh.kumar@linux.ibm.com Subject: mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2

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Link: http://lkml.kernel.org/r/20200326133235.343616-1-aneesh.kumar@linux.ibm.com Fixes: d41e2f3bd546 ("mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case") Signed-off-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com Reported-by: Sachin Sant sachinp@linux.vnet.ibm.com Tested-by: Sachin Sant sachinp@linux.vnet.ibm.com Reviewed-by: Baoquan He bhe@redhat.com Acked-by: Michal Hocko mhocko@suse.com Acked-by: Pankaj Gupta pankaj.gupta.linux@gmail.com Cc: Michael Ellerman mpe@ellerman.id.au Cc: Dan Williams dan.j.williams@intel.com Cc: David Hildenbrand david@redhat.com Cc: Wei Yang richardw.yang@linux.intel.com Cc: Oscar Salvador osalvador@suse.de Cc: Mike Rapoport rppt@linux.ibm.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/sparse.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/mm/sparse.c~mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2 +++ a/mm/sparse.c @@ -781,7 +781,11 @@ static void section_deactivate(unsigned ms->usage = NULL; } memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); - /* Mark the section invalid */ + /* + * Mark the section invalid so that valid_section() + * return false. This prevents code from dereferencing + * ms->usage array. + */ ms->section_mem_map &= ~SECTION_HAS_MEM_MAP; }

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Patches currently in -mm which might be from aneesh.kumar@linux.ibm.com are

mm-sparse-fix-kernel-crash-with-pfn_section_valid-check.patch mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2.patch