rpc.mountd segfaults when trying to mount an nfs share

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I have a pair of QNAP TS859U-RP nas devices running Linux version 2.6.33.2. These boxes are based on Debian. They are experiencing the same failure.

When I try to mount an nfs share as root as following: 

mount nasb:/content /mnt/nasb/blah/

It gives a timeout on the client:

mount: mount to NFS server 'nasb' failed: timed out (retrying).  
mount: mount to NFS server 'nasb' failed: timed out (retrying).

There is also an error written to logs/kmsg on the nas like: 

<6>rpc.mountd[522]: segfault at b73aa078 ip b76fdf56 sp bf8b03a4 error 7 in libuLinux_statistics.so.0.0[b76fd000+3000]  
<6>rpc.mountd[6539]: segfault at b7418078 ip b776bf56 sp bfd69a94 error 7 in libuLinux_statistics.so.0.0[b776b000+3000]  
... repeating

rpc.mountd is restarted, and the device momentarily stops serving nfs requests to all hosts. This device has that very same nfs share mounted on 23 other hosts and functioning as confirmed by running netstat -a | grep nfs | grep ESTAB | wc -l on the nas. I know there is some soft limit to the number of hosts that can mount a particular nfs share but either way it shouldn’t segfault but return some error.

This is a software raid6 volume formatted with ext4. I tried contacting support a few times but have gotten nothing but the standard upgrade/reapply your firmware and reboot response. No satisfaction 🙁 Any ideas on tracking down the error with rpc.mountd/libuLinux_statistics.so would be greatly appreciated.

Thank you in advance.

Answer

Thank you: @malcolmpdx. I think I have it narrowed down to something going south during the firmware upgrade which didn’t update a file.. /usr/lib/libuLinux_statistics.so. I reapplied the firmware update, the file was updated, and the problem has yet to manifest itself again. I couldn’t have done it (at least not in a reasonable time) without your suggestions.

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Source : Link , Question Author : user121843 , Answer Author : user121843

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