Patch Name: PHKL_23171

Patch Description: s700 10.20 ptrace cumulative patch

Creation Date: 01/01/18

Post Date:  01/01/22

Hardware Platforms - OS Releases:
	s700: 10.20

Products: N/A

Filesets:
	OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Superseded

Critical:
	Yes
	PHKL_23171: HANG

Path Name: /hp-ux_patches/s700/10.X/PHKL_23171

Symptoms:
	PHKL_23171:
	(SR: 8606172359   CR: JAGad41619)
	On a multi-processor system, ptrace of a process by multiple
	processes can fail.  This can lead sometimes to process or
	system hangs.

	This defect was introduced with the patch this patch
	supersedes (PHKL_21431) and can only bee seen on
	multi-processor systems.

	PHKL_21431:
	(SR: 5003352484   CR: JAGaa11895)
	Debuggers attempting to work with a child process of a
	process already under debug fail.  The failure is reported
	at the moment the child process to be debugged is forked.
	The following is an example of the error that DDE may
	report:

	"kernel internal error:  Process events (fork, vfork, exit,
	exec) will not be reported."

Defect Description:
	PHKL_23171:
	(SR: 8606172359   CR: JAGad41619)
	Code paths exists which can leave an alpha semaphore locked
	on exit.

	Resolution:
	Calls to ptrace now make sure that alpha semaphores are
	correctly released for all code paths.

	PHKL_21431:
	(SR: 5003352484   CR: JAGaa11895)
	When a process under debug forks out a new child process,
	the debugger, if asked to do so, will also attempt to fork a
	new debugger for the child process.  Since the PT_ATTACH for
	the child process occurs when the child process has not yet
	even run, certain variables have not yet been set and
	additional debugger commands fail to work properly.

	Resolution:
	In order to get the debugged child process to go through the
	proper path and initialize the apropriate variables, this
	process is now forced to go from TSSTOP to TSRUN.  To
	accomplish this correctly, extra synchronization in the
	PT_ATTACH code executed by the debugger was added.  This
	extra synchronization allows the debugged child process to
	complete its initialization before the debugger is allowed
	to continue.

SR:
	5003352484 8606172359

Patch Files:
	/usr/conf/lib/libhp-ux.a(pm_ptrace.o)

what(1) Output:
	/usr/conf/lib/libhp-ux.a(pm_ptrace.o):
		pm_ptrace.c $Date: 2001/01/17 16:13:10 $ $Revision:
			1.6.98.27 $ PATCH_10.20 (PHKL_23171)

cksum(1) Output:
	3606335485 16448 /usr/conf/lib/libhp-ux.a(pm_ptrace.o)

Patch Conflicts: None

Patch Dependencies:
	s700: 10.20: PHKL_16750

Hardware Dependencies: None

Other Dependencies: None

Supersedes:
	PHKL_21431

Equivalent Patches:
	PHKL_23172:
	s800: 10.20

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_23171

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

		swinstall -x autoreboot=true -x match_target=true \
			-s /tmp/PHKL_23171.depot

	By default swinstall will archive the original software in
	/var/adm/sw/patch/PHKL_23171.  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_23171.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_23171.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.