The patch titled Subject: mm/compaction: fix UBSAN shift-out-of-bounds warning has been added to the -mm mm-unstable branch. Its filename is mm-compaction-fix-ubsan-shift-out-of-bounds-warning.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Liu Shixin liushixin2@huawei.com Subject: mm/compaction: fix UBSAN shift-out-of-bounds warning Date: Thu, 23 Jan 2025 10:10:29 +0800

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 Cc: Baolin Wang baolin.wang@linux.alibaba.com Cc: David Hildenbrand david@redhat.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Kemeng Shi shikemeng@huaweicloud.com Cc: Mattew Wilcox willy@infradead.org [English fixes] 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 ---

mm/compaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/compaction.c~mm-compaction-fix-ubsan-shift-out-of-bounds-warning +++ a/mm/compaction.c @@ -631,7 +631,8 @@ 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; _

Patches currently in -mm which might be from liushixin2@huawei.com are

mm-page_isolation-avoid-call-folio_hstate-without-hugetlb_lock.patch mm-compaction-fix-ubsan-shift-out-of-bounds-warning.patch