Server with Unbreakable Enterprise Kernel Becomes Unstable after Being 'rds-ping'ed

(Doc ID 1292928.1)

Last updated on MARCH 08, 2017

Applies to:

Linux OS - Version: Oracle Linux 5.5 with Unbreakable Enterprise Kernel [2.6.32] to Oracle Linux 5.5 with Unbreakable Enterprise Kernel [2.6.32] - Release: OL5U5 to OL5U5
Linux x86-64

Symptoms

In an Infiniband (IB) network environment, Reliable Datagram Sockets (RDS) is enabled and TCP layer is enabled by following <Document 1271342.1>. The Unbreakable Enterprise Kernel over Oracle Linux 5.5 is being used.

Performing tests with rds-stress are successful without any side effect. When one server is tested for response using rds-ping, the pings are successful but pinged host runs into trouble. One symptom is that the target host dumps the following on the serial console:

rds_connect_complete: Cannot transition to state UP, current state is 4
RDS: rds_conn_shutdown: failed to transition to state DOWN, current state is 4
rds_connect_complete: Cannot transition to state UP, current state is 4
RDS: rds_conn_shutdown: failed to transition to state DOWN, current state is 4

After running rds-ping for some time (that will depend on the system configuration / capacity etc.):

System load (loadavg) increases gradually
After some time processes cannot be killed
Logging off seems to hang
New processes cannot be started
Logons fail
Running shutdown / reboot hangs
Sysrq-c or other Sysrq attempts are inconclusive
Hard reboot seems to be the only solution

Changes

Upgraded to Unbreakable Enterprise Kernel (2.6.32 series), from Red Hat Compatible Kernel (2.6.18 series)

Cause

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