On Sun, Dec 20, 2020 at 01:10:37PM -0800, Randy Dunlap wrote: > UBSAN detected a 64-bit shift in log2.h:__roundup_pow_of_two(): > UBSAN: shift-out-of-bounds in ./include/linux/log2.h:57:13 > shift exponent 64 is too large for 64-bit type 'long unsigned int' > > This is during a call from mm/readahead.c:ondemand_readahead(), > get_init_ra_size(), where the 'size' parameter must have been > extremely large (or "negative"). Actually, I think it was zero, which is the real bug that should be fixed.
