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mm/page_isolation: fix potential warning from user

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It makes sense to call the WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE)
from start_isolate_page_range(), but should avoid triggering it from
userspace, i.e, from is_mem_section_removable() because it could crash
the system by a non-root user if warn_on_panic is set.

While at it, simplify the code a bit by removing an unnecessary jump
label.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Qian Cai <[email protected]>
Suggested-by: Michal Hocko <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Qian Cai authored and Linus Torvalds committed 2020-01-31 10:30:39 -08:00
1 parent 4a55c0474a
commit 3d680bdf60
2 files changed
+15 -14
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mm/page_alloc.c
+4 -7
View File
@@ -8214,7 +8214,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
if (is_migrate_cma(migratetype))
return NULL;
goto unmovable;
return page;
}
for (; iter < pageblock_nr_pages; iter++) {
@@ -8224,7 +8224,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
page = pfn_to_page(pfn + iter);
if (PageReserved(page))
goto unmovable;
return page;
/*
* If the zone is movable and we have ruled out all reserved
@@ -8244,7 +8244,7 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
unsigned int skip_pages;
if (!hugepage_migration_supported(page_hstate(head)))
goto unmovable;
return page;
skip_pages = compound_nr(head) - (page - head);
iter += skip_pages - 1;
@@ -8286,12 +8286,9 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page,
* is set to both of a memory hole page and a _used_ kernel
* page at boot.
*/
goto unmovable;
return page;
}
return NULL;
unmovable:
WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
return pfn_to_page(pfn + iter);
}
#ifdef CONFIG_CONTIG_ALLOC
mm/page_isolation.c
+11 -7
View File
@@ -54,14 +54,18 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
out:
spin_unlock_irqrestore(&zone->lock, flags);
if (!ret)
if (!ret) {
drain_all_pages(zone);
else if ((isol_flags & REPORT_FAILURE) && unmovable)
/*
* printk() with zone->lock held will guarantee to trigger a
* lockdep splat, so defer it here.
*/
dump_page(unmovable, "unmovable page");
} else {
WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
if ((isol_flags & REPORT_FAILURE) && unmovable)
/*
* printk() with zone->lock held will likely trigger a
* lockdep splat, so defer it here.
*/
dump_page(unmovable, "unmovable page");
}
return ret;
}