6.13-stable review patch. If anyone has any objections, please let me know.
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From: Liu Shixin liushixin2@huawei.com
commit d1366e74342e75555af2648a2964deb2d5c92200 upstream.
syzkaller reported a UBSAN shift-out-of-bounds warning of (1UL << order) in isolate_freepages_block(). The bogus compound_order can be any value because it is union with flags. Add back the MAX_PAGE_ORDER check to fix the warning.
Link: https://lkml.kernel.org/r/20250123021029.2826736-1-liushixin2@huawei.com Fixes: 3da0272a4c7d ("mm/compaction: correctly return failure with bogus compound_order in strict mode") Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kemeng Shi shikemeng@huaweicloud.com Acked-by: David Hildenbrand david@redhat.com Reviewed-by: Oscar Salvador osalvador@suse.de Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: David Hildenbrand david@redhat.com Cc: Kemeng Shi shikemeng@huaweicloud.com Cc: Matthew Wilcox willy@infradead.org Cc: Mel Gorman mgorman@techsingularity.net Cc: Nanyong Sun sunnanyong@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/compaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/compaction.c +++ b/mm/compaction.c @@ -630,7 +630,8 @@ static unsigned long isolate_freepages_b if (PageCompound(page)) { const unsigned int order = compound_order(page);
- if (blockpfn + (1UL << order) <= end_pfn) { + if ((order <= MAX_PAGE_ORDER) && + (blockpfn + (1UL << order) <= end_pfn)) { blockpfn += (1UL << order) - 1; page += (1UL << order) - 1; nr_scanned += (1UL << order) - 1;