Patch Name:  PHKL_7213

Patch Description: s700 10.01 panic: Spinlock deadlock!

Creation Date: 96/04/08

Post Date:  96/04/08

Hardware Platforms - OS Releases:
        s700: 10.01

Products: N/A

Filesets:
        OS-Core.CORE-KRN

Automatic Reboot?: Yes

Status: General Release

Critical:
        Yes
        PHKL_7213: PANIC

Path Name:  /hp-ux_patches/s700/10.X/PHKL_7213

Symptoms:
        PHKL_7213:
        The system would panic with:
           panic: Spinlock deadlock!

Defect Description:
        PHKL_7213:
        There was a possible race condition between the execve() and
        sched() code paths, causing to loop forever in mlockedpreg()
        while holding spinlocks. Eventually, the system would panic
        with "Spinlock deadlock!". Typical kernel stack traces would
        look like the following:
        Processor X:
           panic+0x0010
           too_much_time+0x0240
           wait_for_lock_spinner+0x02c4
           wait_for_lock_4way+0x002c
           sl_retry+0x0018
           insertpreg+0x0024
           attachreg+0x00ac
           createU+0x0138
           vfork_createU+0x0058
           getxfile+0x08ac
           execve+0x0c58
           syscall+0x01f4
        Processor Y:
           mlockedpreg+0x0048
           deactivate_inactiveproc+0x0060
           foreach_process+0x0054
           deactivate_inactive+0x00b8
           sched+0x021c
           main+0x09b4
           $vstart+0x003d

SR:
        1653164160

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

what(1) Output:
        /usr/conf/lib/libhp-ux.a(vm_plock.o):
                vm_plock.c    $Date: 96/04/08 08:16:05 $ $Revision:
                        1.2.71.9 $ PATCH_10.01 (PHKL_7213)

cksum(1) Output:
        868314198 5732 /usr/conf/lib/libhp-ux.a(vm_plock.o)

Patch Conflicts: None

Patch Dependencies:  None

Hardware Dependencies:  None

Other Dependencies:  None

Supersedes:  None

Equivalent Patches:
        PHKL_7214:
        s800: 10.01

Patch Package Size:  60 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_7213

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

                swinstall -x autoreboot=true -x match_target=true \
                        -s /tmp/PHKL_7213.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_7213.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_7213.  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_7213.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_7213.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions:  None