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Patch Name: PHKL_23665
Patch Description: s700_800 11.11 thread nostop, preemption_point priority fix
Creation Date: 01/07/17
Post Date: 01/08/02
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Status: General Superseded
Critical:
No (superseded patches were critical)
PHKL_24257: OTHER
Hung, Unkillable Process
Category Tags:
defect_repair general_release critical manual_dependencies
Path Name: /hp-ux_patches/s700_800/11.X/PHKL_23665
Symptoms:
PHKL_23665:
( SR:8606128017 CR:JAGac78818 )
vhand priority does not match scheduling policy for brief
durations.
PHKL_24257:
( SR:8606159451 CR:JAGad28779 ) Duplicate
( SR:8606103740 CR:JAGab70789 )
A multi-threaded process being executed over NFS can become
hung and unkillable while performing either a fork, core,
setrlimit, SIGSTOP, or debugger operations. This can happen
with mutiple threads in different processes competing for
the same resource when one thread is stopped.
Defect Description:
PHKL_23665:
( SR:8606128017 CR:JAGac78818 )
When vhand's priority is increased due to it being
preempted, there is a race with other threads which are
also raising vhand's priority at the same time. Thus,
when vhand switches back to run again, its policy and
priority number do not match. The priority and policy
will be back in sync once the thread which elevated the
priority of vhand is restored to run again.
Resolution:
Preemption_point no longer elevates the priority of the
preempted thread.
PHKL_24257:
( SR:8606159451 CR:JAGad28779 ) Duplicate
( SR:8606103740 CR:JAGab70789 )
A thread acquires a lock and then sleeps interruptibly. The
interruptible sleep permits the thread to be stopped. Any
other thread attempting to acquire this lock will sleep
uninterruptibly until the lock is available. This
uninterruptible thread is also unkillable. This introduces
a deadlock potential in multi-threaded processes: when a
thread holding the lock, a thread desiring the lock, and a
third thread doing one of fork, setrlimit, core, SIGSTOP, or
debugger operations, all occur at the same time in the
same process, the deadlock is reached. The only way to
resolve the deadlock is to reboot the system. A similar
situation can occur when threads in different processes
are competing for the same NFS resource and the thread that
owns that resource is stopped via a signal, a debugger,
or a ctrl-Z.
This patch is part of a set of five patches (PHKL_24253,
PHKL_24254,PHKL_24255,PHKL_24256,PHKL_24257) that enable
P_NOSTOP, a new feature that prevents a process from being
unkillable. Each patch is independently installable.
Without all five installed, P_NOSTOP will be unavailable.
In order to prevent the process executed over NFS from
becoming unkillable, NFS must use the P_NOSTOP feature.
Usage of this feature was added to PHNE_23502.
Resolution:
If a thread acquires a lock and then sleeps interruptibly,
it is not permitted to be stopped if P_NOSTOP is set. This
prevents this thread from becoming unkillable and prevents
the deadlock.
SR:
8606103740 8606128017 8606159451
Patch Files:
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
/usr/conf/lib/libpm.a(pm_swtch.o)
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
/usr/conf/lib/libpm.a(pm_swtch.o)
what(1) Output:
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
/usr/conf/lib/libpm.a(pm_swtch.o):
pm_swtch.c $Date: 2001/07/10 15:07:08 $Revision: r11
.11/5 PATCH_11.11 (PHKL_23665)
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
/usr/conf/lib/libpm.a(pm_swtch.o):
pm_swtch.c $Date: 2001/07/10 15:07:08 $Revision: r11
.11/5 PATCH_11.11 (PHKL_23665)
cksum(1) Output:
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_32,v=HP:
3707628749 46424 /usr/conf/lib/libpm.a(pm_swtch.o)
OS-Core.CORE2-KRN,fr=B.11.11,fa=HP-UX_B.11.11_64,v=HP:
2272126828 113456 /usr/conf/lib/libpm.a(pm_swtch.o)
Patch Conflicts: None
Patch Dependencies: None
Hardware Dependencies: None
Other Dependencies:
PHKL_24257: If NFS is installed on the system, all five
patches (PHNE_23502, PHKL_24253, PHKL_24254,PHKL_24255,
PHKL_24256, PHKL_24257) are required to resolve the process
hang/deadlock due to unkillable processes executed over NFS.
However, if NFS is not in use, none of these patches are
required.
Supersedes:
PHKL_24257
Equivalent Patches: None
Patch Package Size: 180 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_23665
5. Run swinstall to install the patch:
swinstall -x autoreboot=true -x patch_match_target=true \
-s /tmp/PHKL_23665.depot
By default swinstall will archive the original software in
/var/adm/sw/save/PHKL_23665. If you do not wish to retain a
copy of the original software, include the patch_save_files
option in the swinstall command above:
-x patch_save_files=false
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_23665.text file is
available in the product readme:
swlist -l product -a readme -d @ /tmp/PHKL_23665.depot
To put this patch on a magnetic tape and install from the
tape drive, use the command:
dd if=/tmp/PHKL_23665.depot of=/dev/rmt/0m bs=2k
Special Installation Instructions: None
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