Created attachment 132947 [details] dmesg output
Description of problem: Since booting kernel-2.6.17-1.2142_FC4 (and -1.2141), this system will periodically lock up while accessing a NFS mount. I've attached partial output from a process trace (all that dmesg could capture). There is a hung idl process, as well as a couple ps processes that are hung.
it appears all the process in the NFS code seem to be trying to flush pages out... But I guess the hang comes from the fact that pdflush is also trying to free pages... Note how its sleeping in nfs_wait_on_request().... So at the end of the day it appears we are in a low memory situation... A couple of things, 1) is there any network traffic going to the server during this period? If so, what type messages are they? 2) Could you please post a sysctl-M memory trace?
[This comment added as part of a mass-update to all open FC4 kernel bugs] FC4 has now transitioned to the Fedora legacy project, which will continue to release security related updates for the kernel. As this bug is not security related, it is unlikely to be fixed in an update for FC4, and has been migrated to FC5. Please retest with Fedora Core 5. Thank you.
Have not had a reoccurrence recently. Closing for now.