Linux kernel (drivers/infiniband/sw/siw): A remote peer crashes the node during connection setup. When the MPA

Impact

A remote peer crashes the node during connection setup. When the MPA handshake reply arrives incomplete, siw reports the connect-reply event twice and the iWARP CM hits a hard BUG() - an immediate kernel panic driven entirely from the wire, before any application-level authentication.

Who can reach it

Network-reachable and pre-authentication: a peer the node connects to (or that controls TCP segmentation toward it) sends the MPA reply split so siw sees a partial read. The upstream reproducer is stock ib_send_lat between two hosts, so this fires on ordinary traffic patterns, not just hostile crafting. Requires the siw (soft-iWARP) module to be loaded.

What to do

No fixed release is published in this record - apply the listed stable fix commits or run a current stable kernel. Interim: unload/blacklist siw unless soft-iWARP is genuinely in use, and restrict which peers may complete iWARP connections to the node.

References