Patch Name: PHKL_23196

Patch Description: s700_800 11.11 Fix for locking problem in I/O (GIO)

Creation Date: 01/02/01

Post Date:  01/05/01

Hardware Platforms - OS Releases:
	s700: 11.11
	s800: 11.11

Products: N/A

Filesets:
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP

Automatic Reboot?: Yes

Status: General Release

Critical:
	Yes
	PHKL_23196: PANIC
		The panic happened in certain error path, and it
		is hard to reproduce.

Category Tags:
	defect_repair general_release critical panic

Path Name: /hp-ux_patches/s700_800/11.X/PHKL_23196

Symptoms:
	PHKL_23196:
	( SR:8606171253 CR:JAGad40517 )
	While running the TPC-C benchmark, a disk drive
	on the system failed.
	Within seconds, the system paniced.
	The stack was as following:
	    panic+0x6c
	    report_trap_or_int_and_panic+0x94
	    interrupt+0x208
	    $ihndlr_rtn+0x0
	    lock_write+0x78
	    mod_rw_wrlock+0x10
	    io_dev_to_node+0xe4
	    lv_dev_to_hwpathstr+0x18
	    lv_diag_log+0x84
	    lv_io_error_processing+0x174
	    lv_end+0x3d8
	    biodone+0x100
	    scsi_cbfn+0x414
	    fcparray_scsi_comp+0x1c8
	    td_io_done+0x9c
	    td_cdb_cbfn_start+0xb0
	    td_isr+0x3ac
	    sapic_interrupt+0x2c
	    mp_ext_interrupt+0x354
	    ivti_patch_to_nop3+0x0
	    idle+0x1c0
	    swidle_exit+0x0

Defect Description:
	PHKL_23196:
	( SR:8606171253 CR:JAGad40517 )
	The problem is that LVM calls io_dev_to_node() on
	the interrupt stack, and io_dev_to_node() tries to
	acquire a read-write lock (MOD_RW_WRLOCK) to protect
	the device switch table. It is not allowed to
	acquire this lock on the interrupt stack (because it
	might sleep), so the kernel panics.

	Resolution:
	When the code wants to acquire the lock, it first
	checks to see whether it is running on the interrupt
	stack or not. If it is, it does not acquire the
	lock. The device switch table is still protected
	through some higher level checks. The change was
	made only to those functions which acquires the
	lock and also could be on ICS.

SR:
	8606171253

Patch Files:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	/usr/conf/lib/libio.a(gio_kdev.o)
	/usr/conf/lib/libio.a(gio_search.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libio.a(gio_kdev.o)
	/usr/conf/lib/libio.a(gio_search.o)

what(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	/usr/conf/lib/libio.a(gio_kdev.o):
		gio_kdev.c $Date: 2000/12/11 16:38:12 $Revision: r11
			.11/1 PATCH_11.11 (PHKL_23196)
	/usr/conf/lib/libio.a(gio_search.o):
		gio_search.c $Date: 2000/12/11 16:38:12 $Revision: r
			11.11/1 PATCH_11.11 (PHKL_23196)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	/usr/conf/lib/libio.a(gio_kdev.o):
		gio_kdev.c $Date: 2000/12/11 16:38:12 $Revision: r11
			.11/1 PATCH_11.11 (PHKL_23196)
	/usr/conf/lib/libio.a(gio_search.o):
		gio_search.c $Date: 2000/12/11 16:38:12 $Revision: r
			11.11/1 PATCH_11.11 (PHKL_23196)

cksum(1) Output:
	
	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
	978076760 15896 /usr/conf/lib/libio.a(gio_kdev.o)
	362247534 16344 /usr/conf/lib/libio.a(gio_search.o)

	OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
	1225943936 41976 /usr/conf/lib/libio.a(gio_kdev.o)
	2313181052 34792 /usr/conf/lib/libio.a(gio_search.o)

Patch Conflicts: None

Patch Dependencies: None

Hardware Dependencies: None

Other Dependencies: None

Supersedes: None

Equivalent Patches: None

Patch Package Size: 130 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_23196

	5. Run swinstall to install the patch:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -s /tmp/PHKL_23196.depot

	By default swinstall will archive the original software in 
	/var/adm/sw/save/PHKL_23196.  If you do not wish to retain a
	copy of the original software, use the patch_save_files option:

		swinstall -x autoreboot=true -x patch_match_target=true \
			  -x patch_save_files=false -s /tmp/PHKL_23196.depot

	WARNING: If patch_save_files is false when a patch is installed,
		 the patch cannot be deinstalled.  Please be careful
		 when using this feature.

	For future reference, the contents of the PHKL_23196.text file is 
	available in the product readme:

		swlist -l product -a readme -d @ /tmp/PHKL_23196.depot

	To put this patch on a magnetic tape and install from the
	tape drive, use the command:

		dd if=/tmp/PHKL_23196.depot of=/dev/rmt/0m bs=2k

Special Installation Instructions: None