13.3-STABLE - Fatal trap 12

Hi all,

after upgrading of 4 same hardware servers last week from source, I
have a strange behavior on one of them. There occurs a panic
sporadically (several times a day).

I supposed there is a hardware error, but I exchanged the disk between 2
servers and the problem moved to the other server, with the disks. All
the servers runs more or less the same set of software:

- bind
- sendmail
- mysql
- squid
- apache
- haproxy

Recently, I switched off squid and the panic occurs less frequently. As
far as I understand the problem, it should not be a panic of the system,
if there is a user software error.

Here is the list of functioning servers:

- 13.3-STABLE stable/13-n258054-12bd1341d2aa
- 13.3-STABLE stable/13-n258052-7f936b0cba08
- 13.3-STABLE stable/13-n258052-7f936b0cba08


The problematic server is:
- 13.3-STABLE stable/13-n258056-8b5eb0cf6c4f

Here is usual error:

Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x20
fault code              = supervisor read data, page not present
instruction pointer     = 0x20:0xffffffff806ee100
stack pointer           = 0x28:0xfffffe0208d08df0
frame pointer           = 0x28:0xfffffe0208d08e00
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = resume, IOPL = 0
current process         = 7 (pf purge)
trap number             = 12
panic: page fault
cpuid = 0


If you are interested, I can provide a link to the core dumps.

Please, could you provide any hints, where problems could be? Is there
any problem with pf in 13.3-STABLE that I do not realize? Why is not
occurring on the other systems?

Thank you very much.

Regards,

lk