mainline inclusion from mainline-v6.14-rc1 commit d1366e74342e75555af2648a2964deb2d5c92200 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IBK4CZ Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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: Liu Shixin <liushixin2@huawei.com> --- mm/compaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/compaction.c b/mm/compaction.c index e2735752c374..4a3a5c7607f3 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -650,7 +650,8 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, 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; -- 2.34.1