In the Linux kernel, the following vulnerability has been resolved: bnxt_re: avoid shift undefined behavior in bnxt_qplib_alloc_init_hwq Undefined behavior is triggered when bnxt_qplib_alloc_init_hwq is called with hwq_attr->aux_depth != 0 and hwq_attr->aux_stride == 0. In that case, "roundup_pow_of_two(hwq_attr->aux_stride)" gets called. roundup_pow_of_two is documented as undefined for 0. Fix it in the one caller that had this combination. The undefined behavior was detected by UBSAN: 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' CPU: 24 PID: 1075 Comm: (udev-worker) Not tainted 6.9.0-rc6+ #4 Hardware name: Abacus electric, s.r.o. - servis@abacus.cz Super Server/H12SSW-iN, BIOS 2.7 10/25/2023 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x30 __ubsan_handle_shift_out_of_bounds.cold+0x61/0xec __roundup_pow_of_two+0x25/0x35 [bnxt_re] bnxt_qplib_alloc_init_hw…