Patch Name: PHKL_26698

Patch Description: s700_800 11.11 umount-mkfs panic; HFS mount/umount perf

Creation Date: 02/06/05

Post Date:  02/07/23

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:
	No (superseded patches were critical)
	PHKL_23811: PANIC

Category Tags:
	defect_repair enhancement general_release critical panic

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_26698

Symptoms:
	PHKL_26698:
	( SR:8606247419 CR:JAGae13857 )
	Enhancement:  This product update is a member of a set
	which improve the performance of mount(2) and umount(2).
	The full list of product updates that address this
	performance improvement are: PHKL_26239, PHKL_26694,
	PHKL_26695, PHKL_26698, and PHKL_27211.

	Each of these product updates may be installed independently
	of the others.  Each provides an incremental performance
	improvement.

	PHKL_23811:
	( SR:8606174452 CR:JAGad43698 )
	This panic could occur when running umount, and
	mkfs (or fsck) at the same time on a system.

	q4> examine panicstr using s
	Data page fault

	Following is the trace for this problem:

	Stack trace of event 0:

	  stack trace for event 0
	  crash event was a panic
	  panic+0x6c
	  report_trap_or_int_and_panic+0x94
	  trap+0xed4
	  nokgdb+0x8
	  bcopy_pcxu_method+0x0
	  sbupdate+0x180
	  ufs_sync+0x2bc
	  update+0x4c
	  sync+0x28
	  syscall+0x204
	  $syscallrtn+0x0

Defect Description:
	PHKL_26698:
	( SR:8606247419 CR:JAGae13857 )
	This product update contains minor changes necessary to
	improve the performance of umount(2) for HFS filesystem.
	HFS unnecessarily invalidated buffers in the buffer
	cache resulting in performance degradation.

	Resolution:
	Improve flushing of dirty buffers during umount(2)
	kernel service processing in HFS.

	PHKL_23811:
	( SR:8606174452 CR:JAGad43698 )
	The panic is due to a race between two threads
	one running unmount() and other mkfs(). The unmount() thread
	proceeds after verifying that no one is referencing the
	filesystem. Another thread running mkfs() is unaware that
	the filesystem is being unmounted, proceeds to update its
	superblock data using sbupdate(). The unmount() thread
	which is slightly ahead in the race frees up the filesystem
	structure and removes it from the mounthash list. When the
	thread running mkfs() tries to reference the freed up
	filesystem structure, data page fault occurs.

	Resolution:
	Enforce locks when referencing mount and filesystem data
	structures in unmount()'s execution path. Also when ufs_sync
	is called to update superblock data for all filesystems
	it should ignore the ones that are in the process of being
	unmounted.

SR:
	8606174452 8606247419

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

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libufs.a(ufs_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/libufs.a(ufs_vfsops.o):
		ufs_vfsops.c $Date: 2002/03/14 12:49:49 $Revision: r
			11.11/2 PATCH_11.11 (PHKL_26698)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libufs.a(ufs_vfsops.o):
		ufs_vfsops.c $Date: 2002/03/14 12:49:49 $Revision: r
			11.11/2 PATCH_11.11 (PHKL_26698)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	2037857288 24076 /usr/conf/lib/libufs.a(ufs_vfsops.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	2492997862 57280 /usr/conf/lib/libufs.a(ufs_vfsops.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes:
	PHKL_23811 

Equivalent Patches: None

Patch Package Size: 110 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_26698

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_26698.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_26698.  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_26698.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_26698.depot

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

		dd if=/tmp/PHKL_26698.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None