Hi, On Wed, Mar 15, 2023 at 06:38:00PM +0300, Kirill A. Shutemov wrote: > fix min() warning > > Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Link: https://lore.kernel.org/oe-kbuild-all/202303152343.D93IbJmn-lkp@xxxxxxxxx/ > Signed-off-by: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> > Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> > Cc: Zi Yan <ziy@xxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> This patch results in various boot failures (hang) on arm targets in linux-next. Debug messages reveal the reason. ########### MAX_ORDER=10 start=0 __ffs(start)=-1 min()=10 min_t=-1 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If start==0, __ffs(start) returns 0xfffffff or (as int) -1, which min_t() interprets as such, while min() apparently uses the returned unsigned long value. Obviously a negative order isn't received well by the rest of the code. Guenter > --- > mm/memblock.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memblock.c b/mm/memblock.c > index 338b8cb0793e..7911224b1ed3 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -2043,7 +2043,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end) > int order; > > while (start < end) { > - order = min(MAX_ORDER, __ffs(start)); > + order = min_t(int, MAX_ORDER, __ffs(start)); > > while (start + (1UL << order) > end) > order--; > -- > 2.39.2
