The patch titled
Subject: mm/page_alloc.c: call kernel_map_pages in unset_migrateype_isolate
has been added to the -mm tree. Its filename is
mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate.patch
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------------------------------------------------------
From: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Subject: mm/page_alloc.c: call kernel_map_pages in unset_migrateype_isolate
Commit 3c605096d315 ("mm/page_alloc: restrict max order of merging on
isolated pageblock") changed the logic of unset_migratetype_isolate to
check the buddy allocator and explicitly call __free_pages to merge. The
page that is being freed in this path never had prep_new_page called so
set_page_refcounted is called explicitly but there is no call to
kernel_map_pages. With the default kernel_map_pages this is mostly
harmless but if kernel_map_pages does any manipulation of the page tables
(unmapping or setting pages to read only) this may trigger a fault:
alloc_contig_range test_pages_isolated(ceb00, ced00) failed
Unable to handle kernel paging request at virtual address ffffffc0cec00000
pgd = ffffffc045fc4000
[ffffffc0cec00000] *pgd=0000000000000000
Internal error: Oops: 9600004f [#1] PREEMPT SMP
Modules linked in: exfatfs
CPU: 1 PID: 23237 Comm: TimedEventQueue Not tainted 3.10.49-gc72ad36-dirty #1
task: ffffffc03de52100 ti: ffffffc015388000 task.ti: ffffffc015388000
PC is at memset+0xc8/0x1c0
LR is at kernel_map_pages+0x1ec/0x244
Fix this by calling kernel_map_pages to ensure the page is set in the
page table properly
Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Laura Abbott <lauraa@xxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Zhang Yanfei <zhangyanfei@xxxxxxxxxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Gioh Kim <gioh.kim@xxxxxxx>
Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_isolation.c | 1 +
1 file changed, 1 insertion(+)
diff -puN mm/page_isolation.c~mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate mm/page_isolation.c
--- a/mm/page_isolation.c~mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate
+++ a/mm/page_isolation.c
@@ -103,6 +103,7 @@ void unset_migratetype_isolate(struct pa
if (!is_migrate_isolate_page(buddy)) {
__isolate_free_page(page, order);
+ kernel_map_pages(page, (1 << order), 1);
set_page_refcounted(page);
isolated_page = page;
}
_
Patches currently in -mm which might be from lauraa@xxxxxxxxxxxxxx are
mm-page_alloc-call-kernel_map_pages-in-unset_migrateype_isolate.patch
mm-cma-debugfs-interface.patch
mm-cma-allocation-trigger.patch
mm-cma-release-trigger.patch
mm-cma-allocation-trigger-fix.patch
cma-debug-document-new-debugfs-interface.patch
mm-dont-offset-memmap-for-flatmem.patch
seccomp-allow-compat-sigreturn-overrides.patch
arm-use-asm-generic-for-seccomph.patch
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