Patch Name: PHKL_25238

Patch Description: s700_800 11.11 NFS nfsd deadlock

Creation Date: 01/09/26

Post Date:  01/09/27

Hardware Platforms - OS Releases:
	s700: 11.11
	s800: 11.11

Products: N/A

Filesets:
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP

Automatic Reboot?: Yes

Status: General Release

Critical:
	Yes
	PHKL_25238: HANG
		All NFS processes and swapper process hang.

Category Tags:
	defect_repair general_release critical halts_system

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_25238

Symptoms:
	PHKL_25238:
	( SR:8606219675 CR:JAGad88815 )
	NFS and the virtual memory swapper process may hang when a
	system is under memory pressure and using executables
	through NFS loopback mounts.  'rpcinfo -u <hostname> nfs'
	calls will hang and the following message may appear:

	NFS server not responding

Defect Description:
	PHKL_25238:
	( SR:8606219675 CR:JAGad88815 )
	The NFS hang is a result of a deadlock that only occurs when
	the system is under extreme memory pressure and some files
	are being used through a NFS loop-back mount.  While in the
	midst of reactivating, a process (say P1) eventually blocks
	waiting on the region lock for one of the process's regions.
	If the lock in question is held by a another process (say
	P2) that encountered a page-fault on that region, a deadlock
	could occur if the region is NFS mounted.  If all the NFS
	daemons are deactivated due to the machine being under very
	heavy memory pressure, when P2 attempts to get attribute
	information through an RPC call to an NFS daemon, it will
	fail to complete and P2 will not release the region lock.
	This prevents the swapper from reactivating P1 or any of the
	NFS daemons on the system.

	Resolution:
	The region lock is now dropped before calling the function
	that makes the RPC call through the NFS daemons.  The lock
	is reacquired after the call returns.  This prevents the
	deadlock over the region lock.

SR:
	8606219675

Patch Files:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	/usr/conf/lib/libvm.a(remote_vm.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libvm.a(remote_vm.o)

what(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	/usr/conf/lib/libvm.a(remote_vm.o):
		remote_vm.c $Date: 2001/09/18 15:16:26 $Revision: r1
			1.11/1 PATCH_11.11 (PHKL_25238)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libvm.a(remote_vm.o):
		remote_vm.c $Date: 2001/09/18 15:16:26 $Revision: r1
			1.11/1 PATCH_11.11 (PHKL_25238)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	2982539829 14904 /usr/conf/lib/libvm.a(remote_vm.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	1847890038 26216 /usr/conf/lib/libvm.a(remote_vm.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches:
	PHKL_25237:
	s700: 11.00
	s800: 11.00

Patch Package Size: 70 KBytes

Installation Instructions:
	Please review all instructions and the Hewlett-Packard
	SupportLine User Guide or your Hewlett-Packard support terms
	and conditions for precautions, scope of license,
	restrictions, and, limitation of liability and warranties,
	before installing this patch.
	------------------------------------------------------------
	1. Back up your system before installing a patch.

	2. Login as root.

	3. Copy the patch to the /tmp directory.

	4. Move to the /tmp directory and unshar the patch:

		cd /tmp
		sh PHKL_25238

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_25238.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_25238.  If you do not wish to retain a
	copy of the original software, include the patch_save_files
	option in the swinstall command above:

		-x patch_save_files=false

	WARNING: If patch_save_files is false when a patch is installed,
		 the patch cannot be deinstalled.  Please be careful
		 when using this feature.

	For future reference, the contents of the PHKL_25238.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_25238.depot

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHKL_25238.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None