Patch Name: PHKL_21120

Patch Description: s700_800 11.00 patch for kernel stack unwinding

Creation Date: 00/02/24

Post Date:  00/03/06

Hardware Platforms - OS Releases:
	s700: 11.00
	s800: 11.00

Products: N/A

Filesets:
	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,v=HP
	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,v=HP

Automatic Reboot?: Yes

Status: General Release

Critical: No

Category Tags:
	defect_repair general_release

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_21120

Symptoms:
	PHKL_21120:
	( SR: 8606125998 DTS: JAGac46754 )
	Kernel debuggers (eg. q4) would report a partial kernel
	stack trace for kernel stack overflow panics while in
	thandler:

	  q4> trace event 0
	  stack trace for event 0
	  crash event was a panic
	  can't get struct frame_marker at 0x4bf2c00.0x7fff4298
	  q4: (warning) could not load frame from 0x4bf2c00.
	        0x0'7fff42b8
	  can't get save_state at 0x4bf2c00.0x0'7fff3e08
	  panic+0x14
	  report_trap_or_int_and_panic+0x4c
	  trap+0xa14
	  $call_trap+0x38
	  thandler+0x30c

Defect Description:
	PHKL_21120:
	( SR: 860612599 DTS: JAGac4675 )
	This is a defect in the trap handler code causing kernel
	debuggers (eg. q4) to not be able to unwind kernel stack
	overflow panics.  The trap handler code was not checking if
	there was enough space left on the kernel stack to hold its
	save state. As a result, the system could trap while saving
	registers in the trap save state (accessing an address
	passed the end of the kernel stack), and if this trap
	occured before having saved the PC of the previous trap,
	the PC of the previous trap would be lost, thus leaving
	the kernel stack in a non unwind-able state.

	Resolution:
	When allocating space for its save state, the trap handler
	code now makes sure that the save state is fully contains
	within the kernel stack. If there is not enough space to
	hold the save state, the trap handler code switches to the
	interrupt context stack and the system then panics with a
	kernel stack overflow.

SR:
	8606125998

Patch Files:
	
	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,v=HP:
	/usr/conf/lib/libhp-ux.a(asm_rv.o)

	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,v=HP:
	/usr/conf/lib/libhp-ux.a(asm_rv.o)

what(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,v=HP:
	/usr/conf/lib/libhp-ux.a(asm_rv.o):
		asm_rv.s $Date: 2000/02/24 12:33:02 $Revision: r11ro
			s/14 PATCH_11.00 (PHKL_21120)

	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,v=HP:
	/usr/conf/lib/libhp-ux.a(asm_rv.o):
		asm_rv.s $Date: 2000/02/24 12:33:02 $Revision: r11ro
			s/14 PATCH_11.00 (PHKL_21120)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_32,v=HP:
	275295676 20884 /usr/conf/lib/libhp-ux.a(asm_rv.o)

	OS-Core.CORE2-KRN,fr=B.11.00,fa=HP-UX_B.11.00_64,v=HP:
	806534750 27824 /usr/conf/lib/libhp-ux.a(asm_rv.o)

Patch Conflicts: None

Patch Dependencies:
	s700: 11.00: PHKL_18543
	s800: 11.00: PHKL_18543

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches: None

Patch Package Size: 80 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_21120

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_21120.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_21120.  If you do not wish to retain a
	copy of the original software, use the patch_save_files option:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -x patch_save_files=false -s /tmp/PHKL_21120.depot

	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_21120.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_21120.depot

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

		dd if=/tmp/PHKL_21120.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:
	This patch depends on base patch PHKL_18543.
	For successful installation please insure that PHKL_18543
	is already installed, or that PHKL_18543 is included
	in the same depot with this patch and PHKL_18543
	is selected for installation.