BUG #3242: FATAL: could not unlock semaphore: error code 298

The following bug has been logged online:

Bug reference: 3242
Logged by: Marcin Waldowski
Email address: M(dot)Waldowski(at)sulechow(dot)net
PostgreSQL version: 8.2.3 and 8.2.1
Operating system: Windows XP SP2
Description: FATAL: could not unlock semaphore: error code 298
Details:

Hello.

After some time of performace test of our aplication (50 concurrent database
connections making lots of quick transactions with prepared statements) we
found problem in PostgreSQL log - "could not unlock semaphore: error code
298". After that connections were hanged blocked on update operations.

We are investigating problem now. What another information should we
provide?

Log from 8.2.1
2007-04-19 08:52:11 FATAL: could not unlock semaphore: error code 298
2007-04-19 08:52:11 STATEMENT: COMMIT
2007-04-19 08:52:11 WARNING: AbortTransaction while in COMMIT state

Log from 8.2.3
2007-04-19 10:56:13 FATAL: could not unlock semaphore: error code 298
2007-04-19 10:56:13 STATEMENT: update sometable set a = a + $1, b = b + $2,
c = c + $3 where id = $4

Regards, Marcin