Patch Name: PHKL_9909 Patch Description: s700 10.20 system hang due to LVM and VxFS deadlock Creation Date: 97/01/22 Post Date: 97/02/04 Hardware Platforms - OS Releases: s700: 10.20 Products: N/A Filesets: OS-Core.CORE-KRN Automatic Reboot?: Yes Status: General Superseded Critical: Yes PHKL_9909: HANG Path Name: /hp-ux_patches/s700/10.X/PHKL_9909 Symptoms: PHKL_9909: A deadlock can occur on system running LVM, JFS and HFS. The hang was introduced by one process running lvmerge on HFS logical volumes and another process running umount on a JFS logical volume. This deadlock can only occur with the following scenario: (1). Process A is running a lvmerge or a lvsplit on a HFS logical volume (2). Process B is running a mount, umount or sync on a JFS logical volume. Defect Description: PHKL_9909: A deadlock resulted from a process running lvmerge on HFS logical volumes, and another process running umount on a JFS logical volume. The umount process grabs the JFS update sleep lock (used to serialize JFS syncs/mounts/ umounts), calls spec_close to close the device we are unmounting, and eventually gets to a LVM close routine which is sleeping waiting to acquire the LVM volume-group lock. The lvmerge process is holding the LVM volume-group lock and proceeds to call freeze_and_sync_fs_dev() to freeze and sync the file system associated with the device. The routine ufs_freeze() is first called which in turn calls walk_and_freeze_fs() without a pointer to a vfs structure. This proves faulty since update() is now called without a vfsp and will proceed to try and sync every mounted file system instead of just the file system being frozen. So we proceeded to try and sync a JFS file system which first tries to grab the JFS update sleep lock, and a deadlock occurs. This problem can be reproduced by having one process running a lvsplit or lvmerge on a HFS logical volume, and another process running a mount, umount or sync on a JFS logical volume. The fix for this problem is to pass the vfsp to walk_and_freeze_fs() from ufs_freeze() instead of the do_sync argument. The routine walk_and_freeze_fs() now uses vfsp when it calls update(). SR: 5003328237 Patch Files: /usr/conf/lib/libufs.a(ufs_vfsops.o) what(1) Output: /usr/conf/lib/libufs.a(ufs_vfsops.o): ufs_vfsops.c $Date: 97/01/22 10:23:07 $ $Revision: 1.20.98.10 $ PATCH_10.20 (PHKL_9909) cksum(1) Output: 1282487902 20372 /usr/conf/lib/libufs.a(ufs_vfsops.o) Patch Conflicts: None Patch Dependencies: None Hardware Dependencies: None Other Dependencies: None Supersedes: None Equivalent Patches: PHKL_9910: s800: 10.20 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_9909 5a. For a standalone system, run swinstall to install the patch: swinstall -x autoreboot=true -x match_target=true \ -s /tmp/PHKL_9909.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_9909.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_9909. 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_9909.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_9909.depot of=/dev/rmt/0m bs=2k Special Installation Instructions: None