Patch Name: PHKL_28842

Patch Description: s700_800 11.11 lofs_mount

Creation Date: 03/04/14

Post Date: 03/04/22

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_28842: HANG

Category Tags:
	defect_repair general_release critical halts_system

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_28842

Symptoms:
	PHKL_28842:
	( SR:8606295017 CR:JAGae58714 )
	System hang will be experienced by using LOFS mount, where
	the mount directory is a softlink to a special directory
	as shown in the following example:
	        mkdir /special_dir
	        ln -s /special_dir /mnt
	        mount -F lofs /special_dir /mnt
	The hang will occur gradually on accessing the LOFS mount
	directory using some commands like ls(1), bdf(1M),
	umount(1M), etc.  A situation will result where the system
	cannot be accessed by telnet(1) and cannot be logged in
	through the console; however, the system might respond to
	ping(1M).  The stack trace of a typical hung process will
	look like the following:

	preArbitration+0x2d4
	wait_for_lock+0x120
	sl_retry+0x1c
	lookuppn+0x2cc
	lookupname+0x40
	chdirec_seg+0x24
	chdirec+0x14
	chdir+0x34
	syscall+0x204
	syscallinit+0x554

Defect Description:
	PHKL_28842:
	( SR:8606295017 CR:JAGae58714 )
	The LOFS mount routine does not check if the vnode for the
	special directory is the same as the vnode for the mount
	directory before performing the mount operation.  This
	creates the same LOFS root vnode as the covered vnode of
	the mount point and thereby creating a loop in the pathname
	lookup routine while trying to access this filesystem.
	This can cause a contention on vfs lock for other processes
	and eventually a system hang.

	Resolution:
	The LOFS mount routine was modified to check if the vnode
	for the special directory is the same as the vnode for the
	mount directory.  If it is the same, the mount operation
	is failed, thus preventing the creation of indefinite
	loops in LOFS.

Enhancement:
	No

SR:
	8606295017

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

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

what(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	/usr/conf/lib/liblofs.a(lo_vfsops.o):
		lo_vfsops.c $Date: 2003/03/12 01:09:10 $Revision: r1
			1.11/1 PATCH_11.11 (PHKL_28842)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/liblofs.a(lo_vfsops.o):
		lo_vfsops.c $Date: 2003/03/12 01:09:10 $Revision: r1
			1.11/1 PATCH_11.11 (PHKL_28842)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	85871441 3780 /usr/conf/lib/liblofs.a(lo_vfsops.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	1175605234 9144 /usr/conf/lib/liblofs.a(lo_vfsops.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches: None

Patch Package Size: 40 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_28842

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_28842.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_28842.  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_28842.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_28842.depot

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

		dd if=/tmp/PHKL_28842.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None