spinlocks storm bug

Hello

I have a report of critical bug (database is temporary unavailability ..
restart is necessary).

A customer use:

PostgreSQL 9.2.4,
24 CPU
140G RAM
SSD disc for all

Database is under high load. There is a few databases with very high number
of similar simple statements. When application produce higher load, then
number of active connection is increased to 300-600 about.

In some moment starts described event - there is a minimal IO, all CPU are
on 100%.

Perf result shows:

354246.00 93.0% s_lock
/usr/lib/postgresql/9.2/bin/postgres
10503.00 2.8% LWLockRelease
/usr/lib/postgresql/9.2/bin/postgres
8802.00 2.3% LWLockAcquire
/usr/lib/postgresql/9.2/bin/postgres
828.00 0.2% _raw_spin_lock
[kernel.kallsyms]
559.00 0.1% _raw_spin_lock_irqsave
[kernel.kallsyms]
340.00 0.1% switch_mm
[kernel.kallsyms]
305.00 0.1% poll_schedule_timeout
[kernel.kallsyms]
274.00 0.1% native_write_msr_safe
[kernel.kallsyms]
257.00 0.1% _raw_spin_lock_irq
[kernel.kallsyms]
238.00 0.1% apic_timer_interrupt
[kernel.kallsyms]
236.00 0.1% __schedule
[kernel.kallsyms]
213.00 0.1% HeapTupleSatisfiesMVCC

We try to limit a connection to 300, but I am not sure if this issue is not
related to some Postgres bug.

Regards

Pavel