Patch Name:  PHKL_7474

Patch Description: s700 10.01 patch for vfork() and spinlock panics

Creation Date: 96/05/08

Post Date:  96/05/09

Hardware Platforms - OS Releases:
        s700: 10.01

Products: N/A

Filesets:
        OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Release

Critical:
        Yes
        PHKL_7474: PANIC
        PHKL_5824: PANIC

Path Name:  /hp-ux_patches/s700/10.X/PHKL_7474

Symptoms:
        PHKL_7474:
        Under a lot of stress, with vfork() being used
        extensively, the system panics with the message:
        panic: vas cnt 0, but still pointing to pregions.

        PHKL_5824:
        This patch fixes a panic "wait_for_lock_spinner:
        Already own this lock!"  The panic only occurs
        on MP systems.

        The stack trace looks like this:

                  panic+0x1c
                  wait_for_lock_spinner+0x30
                  wait_for_lock_4way+0x2c
                  sl_retry+0x18
                  inferior+0x30
                  ttiocom+0xf48
                  pty1_ioctl+0x13c
                  ufs_ioctl+0xec
                  vno_ioctl+0x13c
                  ioctl+0x378

Defect Description:
        PHKL_7474:
        The defect is due to a race in freeproc(). This happens
        when a process does a vfork(), and the process and the
        child exit, without the process waiting for the child.
        In such a case, the processes's parent will try to reap
        the process. Meanwhile, since the child is an orphaned
        zombie, the init process tries to reap the child. This
        results in the init process and the processes's parent
        trying to free the same vas twice.

        PHKL_5824:
        The root cause is a bug in MP locking where the process
        management code attempts to get a lock that it already
        owns.  The fix was to allow for nesting of the locking
        code.

SR:
        1653134304 5000715524

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

what(1) Output:
        /usr/conf/lib/libhp-ux.a(pm_proc.o):
                pm_proc.c $Date: 96/05/07 17:30:09 $ $Revision: 1.8.
                        72.36 $ PATCH_10.01 (PHKL_7474)

cksum(1) Output:
        258330677 11164 /usr/conf/lib/libhp-ux.a(pm_proc.o)

Patch Conflicts: None

Patch Dependencies:  None

Hardware Dependencies:  None

Other Dependencies:  None

Supersedes:
        PHKL_5824

Equivalent Patches:
        PHKL_7476:
        s700: 10.10

Patch Package Size:  70 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_7474

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

                swinstall -x autoreboot=true -x match_target=true \
                        -s /tmp/PHKL_7474.depot

        5b. For a homogeneous NFS Diskless cluster run swcluster on the
            server to install the patch on the server and the clients:

                swcluster -i -b

            This will invoke swcluster in the interactive mode and
            force all clients to be shut down.

            WARNING: All cluster clients must be shut down prior to the
                     patch installation.  Installing the patch while the
                     clients are booted is unsupported and can lead to
                     serious problems.

            The swcluster command will invoke an swinstall session in which
            you must specify:

                alternate root path  -  default is /export/shared_root/OS_700
                source depot path    -  /tmp/PHKL_7474.depot

            To complete the installation, select the patch by choosing
            "Actions -> Match What Target Has" and then "Actions -> Install"
            from the Menubar.

        5c. For a heterogeneous NFS Diskless cluster:

                - run swinstall on the server as in step 5a to install
                  the patch on the cluster server.

                - run swcluster on the server as in step 5b to install
                  the patch on the cluster clients.  The cluster clients
                  must be shut down as described in step 5b.

        By default swinstall will archive the original software in
        /var/adm/sw/patch/PHKL_7474.  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_7474.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_7474.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:  None