There is a kernel API ntb_mw_clear_trans() would pass 0 to both addr and size. This would make xlate_pos negative. [ 23.734156] switchtec switchtec0: MW 0: part 0 addr 0x0000000000000000 size 0x0000000000000000 [ 23.734158] ================================================================================ [ 23.734172] UBSAN: shift-out-of-bounds in drivers/ntb/hw/mscc/ntb_hw_switchtec.c:293:7 [ 23.734418] shift exponent -1 is negative Ensuring xlate_pos is a positive or zero before BIT. Fixes: 1e2fd202f859 ("ntb_hw_switchtec: Check for alignment of the buffer in mw_set_trans()") Signed-off-by: Yajun Deng <yajun.deng@xxxxxxxxx> --- drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c index d6bbcc7b5b90..21468d4fef64 100644 --- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c +++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c @@ -288,7 +288,7 @@ static int switchtec_ntb_mw_set_trans(struct ntb_dev *ntb, int pidx, int widx, if (size != 0 && xlate_pos < 12) return -EINVAL; - if (!IS_ALIGNED(addr, BIT_ULL(xlate_pos))) { + if (xlate_pos >= 0 && !IS_ALIGNED(addr, BIT_ULL(xlate_pos))) { /* * In certain circumstances we can get a buffer that is * not aligned to its size. (Most of the time -- 2.25.1