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_section_valid-check-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2.patch
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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Subject: mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2
add comment
Link: http://lkml.kernel.org/r/20200326133235.343616-1-aneesh.kumar@xxxxxxxxxxxxx
Fixes: d41e2f3bd546 ("mm/hotplug: fix hot remove failure in SPARSEMEM|!VMEMMAP case")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Reported-by: Sachin Sant <sachinp@xxxxxxxxxxxxxxxxxx>
Tested-by: Sachin Sant <sachinp@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Baoquan He <bhe@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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;
}
_
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxx are
mm-sparse-fix-kernel-crash-with-pfn_section_valid-check.patch
mm-sparse-fix-kernel-crash-with-pfn_section_valid-check-v2.patch
