Hi Ming, > I may get one machine with Mellanox NIC, is it easy to setup & reproduce > just in the local machine(both host and target are setup on same machine)? Yes, I have reproduced locally on one machine (using the IP address of the Mellanox NIC as the target IP), with iser enabled on the target, and iscsiadm connected via iser. e.g.: target: /iscsi/iqn.20.../0.0.0.0:3260> enable_iser true iSER enable now: True | | o- portals .................................................................................................... [Portals: 1] | | o- 0.0.0.0:3260 ................................................................................................... [iser] client: # iscsiadm -m node -o update --targetname <target> -n iface.transport_name -v iser # iscsiadm -m node --targetname <target> --login # iscsiadm -m session iser: [3] 172.16.XX.XX:3260,1 iqn.2003-01.org.linux-iscsi.x8664:sn.c46c084919b0 (non-flash) > Please try to trace bio_add_page() a bit via 'bpftrace ./ilo.bt'. Here is the output of this trace from a failed run: # bpftrace lio.bt modprobe: FATAL: Module kheaders not found. Attaching 3 probes... 512 76 4096 0 4096 0 4096 0 4096 76 512 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 4096 0 ^C @start[14475]: 0 @start[14384]: 0 @start[6764]: 0 @start[14477]: 0 @start[7771]: 0 @start[13788]: 0 @start[6879]: 0 @start[11842]: 0 @start[7765]: 0 @start[7782]: 0 @start[14476]: 0 @start[14385]: 0 @start[14474]: 0 @start[11564]: 0 @start[7753]: 0 @start[7786]: 0 @start[7791]: 0 @start[6878]: 0 @start[7411]: 0 @start[14473]: 0 @start[11563]: 0 @start[7681]: 0 @start[7756]: 0 Thanks, Steve