Entire System Hangs And syslog shows "kernel: INFO: task [process]:[pid] blocked for more than 120 seconds" (Doc ID 2264118.1)

Last updated on MAY 11, 2017

Applies to:

Oracle Communications Messaging Server - Version 5.0.0 and later
Information in this document applies to any platform.

Symptoms

On Linux, the entire system may appear to hang even to the point that users are not able to log into the operating system and CPU may reach 100% utilization.

The following is seen many times in syslog:

Apr 9 05:31:45 mailsrv3 kernel: INFO: task imapd:13171 blocked for more than 120 seconds.
Apr 9 05:31:45 mailsrv3 kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Apr 9 05:31:45 mailsrv3 kernel: imapd D ffff8104241de820 0 13171 3625 13179 13167 (NOTLB)
Apr 9 05:31:45 mailsrv3 kernel: ffff81037eb1ff08 0000000000000082 000000000000002a 0000000000000000
Apr 9 05:31:45 mailsrv3 kernel: ffff8101c4f176c0 000000000000000a ffff81004c647860 ffff8104241de820
Apr 9 05:31:45 mailsrv3 kernel: 00143d872232df12 000000000002da60 ffff81004c647a48 00000001b36a99c0
Apr 9 05:31:45 mailsrv3 kernel: Call Trace:
Apr 9 05:31:45 mailsrv3 kernel: [] __down_write_nested+0x7a/0x92
Apr 9 05:31:45 mailsrv3 kernel: [] sys_munmap+0x32/0x59
Apr 9 05:31:45 mailsrv3 kernel: [] system_call+0x7e/0x83
Apr 9 05:31:45 mailsrv3 kernel:
Apr 9 05:47:56 mailsrv3 kernel: possible SYN flooding on port 8143. Sending cookies.
Apr 9 05:49:48 mailsrv3 kernel: nfs: server server1.domain12.com not responding, still trying
Apr 9 05:52:01 mailsrv3 kernel: possible SYN flooding on port 8143. Sending cookies.
Apr 9 05:53:01 mailsrv3 kernel: possible SYN flooding on port 8143. Sending cookies.
Apr 9 05:55:50 mailsrv3 last message repeated 2 times
Apr 9 05:57:51 mailsrv3 last message repeated 2 times
Apr 9 05:59:53 mailsrv3 last message repeated 2 times
Apr 9 06:02:27 mailsrv3 kernel: possible SYN flooding on port 8143. Sending cookies.
Apr 9 10:00:00 mailsrv3 syslogd 1.4.1: restart.

 

Cause

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