Patch Name:  PHKL_10725

Patch Description: s700 10.09[Lev30] semop(2) can cause system to hang

Creation Date: 97/05/22

Post Date:  97/05/28

Hardware Platforms - OS Releases:
        s700: 10.09

Products: N/A

Filesets:
        OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Release

Critical: No

Path Name:  /hp-ux_patches/s700/10.X/PHKL_10725

Symptoms:
        PHKL_10725:

        * A process that uses semop(2) may hang indefinitely.

        The semop() system call would not try to wake up more
        "ncnt" sleepers after the completion of a decrement
        operation resulting in a positive semaphore value.
        The following scenario describes the defect:
        The parent sets semval to 0 and forks 2 children: each
        child tries a decrement operation and goes to sleep
        waiting for semval > 0. Then the parent increments
        semval to 2 thus causing the wakeup of the 1st child,
        but after completing its decrement operation, the 1st
        child would not wakeup the 2nd child!

Defect Description:
        PHKL_10725:

        The semop() system call would not try to wake up more
        "ncnt" sleepers after the completion of a decrement
        operation resulting in a positive semaphore value.
        The following scenario describes the defect:
        The parent sets semval to 0 and forks 2 children: each
        child tries a decrement operation and goes to sleep
        waiting for semval > 0. Then the parent increments
        semval to 2 thus causing the wakeup of the 1st child,
        but after completing its decrement operation, the 1st
        child would not wakeup the 2nd child!

SR:
        0000000000

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

what(1) Output:
        /usr/conf/lib/libhp-ux.a(sysV_sem.o):
                kern/sys/sysV_sem.c, hpuxsysipc, hpux_mcf, mcf21 $Da
                        te: 97/05/22 14:02:55 $ $Revision: 1.5.1.2 P
                        ATCH_10.09 (PHKL_10725) $

cksum(1) Output:
        2618765304 17552 /usr/conf/lib/libhp-ux.a(sysV_sem.o)

Patch Conflicts: None

Patch Dependencies:  None

Hardware Dependencies:  None

Other Dependencies:  None

Supersedes:  None

Equivalent Patches:
        PHKL_10795:
        s700: 10.09

        PHKL_10796:
        s800: 10.09

        PHKL_10920:
        s700: 10.16

        PHKL_10921:
        s800: 10.16

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_10725

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

                swinstall -x autoreboot=true -x match_target=true \
                        -s /tmp/PHKL_10725.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_10725.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.

        By default swinstall will archive the original software in
        /var/adm/sw/patch/PHKL_10725.  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_10725.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_10725.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:  None