HP Tru64 UNIX - 5.1B-4 a_lock timeout panic



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 Advisory Information

RELEASE DATE: 2007-03-28


HP Tru64 UNIX v 5.1B-4 systems have been experiencing a panic with the panic string "a_lock timeout." The problem was caused by a thread being preempted while holding a simple lock. This caused other threads waiting for the lock to timeout and panic.

The solution is to release the lock before preemption, and then reacquire the lock and re-evaluate context upon continuing.

A typical stack trace follows:

0 stop_secondary_cpu
1 panic
2 event_timeout
3 printf
4 panic
5 _a_lock_wait
6 u_anon_fault
7 u_map_fault
8 vm_fault
9 trap
10 _XentMM


The following version is affected:

HP Tru64 UNIX v 5.1B-4 (BL27)


HP is releasing the following ERP kit publicly for use by any customer. The kit uses dupatch to install and will not install over any Customer Specific Patches (CSPs) that have file intersections with the ERP.

The fixes contained in this ERP kit are targeted for availability in the next mainstream patch kit:

HP Tru64 UNIX v 5.1B-5

The kit distributes the following file:


Early Release Patch

HP Tru64 UNIX version: 5.1B-4
ERP Kit Name: T64KIT1001176-V51BB27-E-20070328.tar
Kit Location: