Re: [PATCH] mm/compaction: fix UBSAN shift-out-of-bounds warning

[Oscar Salvador]

On Thu, Jan 23, 2025 at 10:10:29AM +0800, Liu Shixin wrote:
> 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@xxxxxxxxxx>

Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>


-- 
Oscar Salvador
SUSE Labs