| Message ID | 20250123021029.2826736-1-liushixin2@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/compaction: fix UBSAN shift-out-of-bounds warning | expand |
diff --git a/mm/compaction.c b/mm/compaction.c index a2b16b08cbbff..384e4672998e5 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -630,7 +630,8 @@ 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;
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. Fixes: 3da0272a4c7d ("mm/compaction: correctly return failure with bogus compound_order in strict mode") Signed-off-by: Liu Shixin <liushixin2@huawei.com> --- mm/compaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)