Patch Name: PHKL_22155

Patch Description: s700 10.20 pfdat page unlock & exclusive mapped alias fix

Creation Date: 00/08/04

Post Date:  00/08/18

Hardware Platforms - OS Releases:
	s700: 10.20

Products: N/A

Filesets:
	OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Superseded

Critical:
	Yes
	PHKL_22155: PANIC
	PHKL_10460: HANG

Path Name: /hp-ux_patches/s700/10.X/PHKL_22155

Symptoms:
	PHKL_22155:
	(SR: 8606154259   CR: JAGad23577)
	Application issuing large amount of mmap calls to
	map multiple virtual addresses to the same physical
	page (using flags MAP_SHARED|MAP_FILE|MAP_FIXED)
	may cause system panic with the follow stack trace:

	panic: hdl_zero_page: page not mapped

	panic+0x14
	hdl_zero_page+0xc8
	virtual_fault+0x418
	vfault+0x118
	trap+0x280
	nokgdb+0x8

	Trace on other processor shows:

	panic+0x14
	report_trap_or_int_and_panic+0x80
	trap+0xde8
	nokgdb+0x8
	allocpfd_from_pond+0x134
	allocate_page+0x68
	lgpg_vfdfill+0x4c
	virtual_fault+0xc3c
	vfault+0x118
	trap+0x280
	nokgdb+0x8

	PHKL_10460:
	Multiple processes sharing a memory region hang when
	trying to acquire the region lock, while the owner
	of the region lock waits infinitely for a page in the
	region to be unlocked.

Defect Description:
	PHKL_22155:
	(SR: 8606154259   CR: JAGad23577)
	HP-UX handles multiple virtual addresses mapping to the
	same physical page by using virtual address aliasing.
	Large number of overlapping exclusive mapping calls
	(mmap with MAP_SHARED|MAP_FIXED|MAP_FILE) create excessive
	number of virtual address aliases and can exhaust the alias
	entries for physical pages. The exhaustion of alias entries
	results in failed attempts to add a page translation.
	Improper handling of the translation failure results in
	corruption in the free memory list, thus causing an unmapped
	page to be returned from the free memory pond.

	Resolution:
	Handle application requested overlapping exclusive mapping
	without using aliases.

	PHKL_10460:
	The vaslockpages() routine brings in a specified range
	of pages and acquires the pfdat locks for these pages.
	In the case that it does not have the correct access
	rights to all these pages due to the lack of free memory,
	it will unlock the pages and return an ENOMEM. The bug
	is that it unlocks an incorrect number of pages and leaves
	one page locked infinitely during the back out.

SR:
	5003359463 8606154259

Patch Files:
	/usr/conf/lib/libhp-ux.a(hdl_fault.o)
	/usr/conf/lib/libhp-ux.a(hdl_trans.o)
	/usr/conf/lib/libhp-ux.a(vm_misc.o)

what(1) Output:
	/usr/conf/lib/libhp-ux.a(hdl_fault.o):
		hdl_fault.c $Date: 2000/08/04 14:07:31 $ $Revision:
			1.13.98.13 $ PATCH_10.20 (PHKL_22155)
	/usr/conf/lib/libhp-ux.a(hdl_trans.o):
		hdl_trans.c    $Date: 2000/08/04 14:17:48 $ $Revisio
			n: 1.12.98.13 $ PATCH_10.20 (PHKL_22155)
	/usr/conf/lib/libhp-ux.a(vm_misc.o):
		vm_misc.c   $Date: 2000/08/04 14:24:18 $ $Revision:
			1.14.98.15 $ PATCH_10.20 (PHKL_22155)

cksum(1) Output:
	2141662580 13644 /usr/conf/lib/libhp-ux.a(hdl_fault.o)
	3692525272 11016 /usr/conf/lib/libhp-ux.a(hdl_trans.o)
	279897295 8032 /usr/conf/lib/libhp-ux.a(vm_misc.o)

Patch Conflicts: None

Patch Dependencies:
	s700: 10.20: PHKL_16750

Hardware Dependencies: None

Other Dependencies: None

Supersedes:
	PHKL_10460

Equivalent Patches:
	PHKL_22156:
	s800: 10.20

Patch Package Size: 100 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_22155

	5a. For a standalone system, run swinstall to install the
	    patch:

		swinstall -x autoreboot=true -x match_target=true \
			-s /tmp/PHKL_22155.depot

	By default swinstall will archive the original software in
	/var/adm/sw/patch/PHKL_22155.  If you do not wish to retain a
	copy of the original software, you can create an empty file
	named /var/adm/sw/patch/PATCH_NOSAVE.

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

	It is recommended that you move the PHKL_22155.text file to
	/var/adm/sw/patch for future reference.

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

		dd if=/tmp/PHKL_22155.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:
	This patch depends on base patch PHKL_16750 .
	For successful installation, please ensure that PHKL_16750
	is in the same depot with this patch, or PHKL_16750  is
	already installed.