> oops, it should have been (arg4 & 511) != 0. Yep, there they are: # /usr/share/bcc/tools/trace -K 'bio_add_page ((arg4 & 511) != 0) "%d %d", arg3, arg4' PID TID COMM FUNC - 7411 7411 kworker/31:1H bio_add_page 512 76 bio_add_page+0x1 [kernel] sbc_execute_rw+0x28 [kernel] __target_execute_cmd+0x2e [kernel] target_execute_cmd+0x1c1 [kernel] iscsit_execute_cmd+0x1e7 [kernel] iscsit_sequence_cmd+0xdc [kernel] isert_recv_done+0x780 [kernel] __ib_process_cq+0x78 [kernel] ib_cq_poll_work+0x29 [kernel] process_one_work+0x179 [kernel] worker_thread+0x4f [kernel] kthread+0x105 [kernel] ret_from_fork+0x1f [kernel] 7753 7753 kworker/26:1H bio_add_page 4096 76 bio_add_page+0x1 [kernel] sbc_execute_rw+0x28 [kernel] __target_execute_cmd+0x2e [kernel] target_execute_cmd+0x1c1 [kernel] iscsit_execute_cmd+0x1e7 [kernel] iscsit_sequence_cmd+0xdc [kernel] isert_recv_done+0x780 [kernel] __ib_process_cq+0x78 [kernel] ib_cq_poll_work+0x29 [kernel] process_one_work+0x179 [kernel] worker_thread+0x4f [kernel] kthread+0x105 [kernel] ret_from_fork+0x1f [kernel]