# Kernel panic



## CyberCr33p (Dec 6, 2019)

Today and yesterday I had a server crash. The server runs FreeBSD 12.1 without the last "FreeBSD-SA-19:25.mcepsc" patch.

Today I got this:


```
Dec  6 18:27:18 server36.example.com kernel: Fatal trap 12: page fault while in kernel mode
Dec  6 18:27:18 server36.example.com kernel: cpuid = 3; apic id = 03
Dec  6 18:27:18 server36.example.com kernel: fault virtual address#011= 0xffffffff82fb8f38
Dec  6 18:27:18 server36.example.com kernel: fault code#011#011= supervisor read data, page not present
Dec  6 18:27:18 server36.example.com kernel: instruction pointer#011= 0x20:0xffffffff810954b6
Dec  6 18:27:18 server36.example.com kernel: stack pointer#011        = 0x0:0xfffffe00c3c9f600
Dec  6 18:27:18 server36.example.com kernel: frame pointer#011        = 0x0:0xfffffe00c3c9f6b0
Dec  6 18:27:18 server36.example.com kernel: code segment#011#011= base 0x0, limit 0xfffff, type 0x1b
Dec  6 18:27:18 server36.example.com kernel: #011#011#011= DPL 0, pres 1, long 1, def32 0, gran 1
Dec  6 18:27:18 server36.example.com kernel: processor eflags#011= interrupt enabled, resume, IOPL = 0
Dec  6 18:27:18 server36.example.com kernel: current process#011#011= 86140 (nginx)
Dec  6 18:27:18 server36.example.com kernel: trap number#011#011= 12
Dec  6 18:27:18 server36.example.com kernel: panic: page fault
Dec  6 18:27:18 server36.example.com kernel: cpuid = 3
Dec  6 18:27:18 server36.example.com kernel: time = 1575649514
Dec  6 18:27:18 server36.example.com kernel: KDB: stack backtrace:
Dec  6 18:27:18 server36.example.com kernel: #0 0xffffffff80c1d207 at kdb_backtrace+0x67
Dec  6 18:27:18 server36.example.com kernel: #1 0xffffffff80bd053d at vpanic+0x19d
Dec  6 18:27:18 server36.example.com kernel: #2 0xffffffff80bd0393 at panic+0x43
Dec  6 18:27:18 server36.example.com kernel: #3 0xffffffff810a7d2c at trap_fatal+0x39c
Dec  6 18:27:18 server36.example.com kernel: #4 0xffffffff810a7d79 at trap_pfault+0x49
Dec  6 18:27:18 server36.example.com kernel: #5 0xffffffff810a736f at trap+0x29f
Dec  6 18:27:18 server36.example.com kernel: #6 0xffffffff8108132c at calltrap+0x8
Dec  6 18:27:18 server36.example.com kernel: #7 0xffffffff80f0c340 at vm_fault_hold+0x1b90
Dec  6 18:27:18 server36.example.com kernel: #8 0xffffffff80f0a760 at vm_fault+0x60
Dec  6 18:27:18 server36.example.com kernel: #9 0xffffffff810a7e94 at trap_pfault+0x164
Dec  6 18:27:18 server36.example.com kernel: #10 0xffffffff810a74fb at trap+0x42b
Dec  6 18:27:18 server36.example.com kernel: #11 0xffffffff8108132c at calltrap+0x8
```

Do you think it's hardware related?


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## ralphbsz (Dec 6, 2019)

Possible. Could be memory error (overclocked motherboard? inexpensive memory?) creating a wrong address in the kernel, and then the kernel trying to dereference it. But: The address creating the fault seems plausible (it's printed above: 0xffffffff82fb8f38), so it could also be a software problem in the kernel.

Exactly what version are you running? Can you reproduce this with a stock precompiled version?


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## CyberCr33p (Dec 6, 2019)

I test memory using memtester and didn't find any issue. Also the disks look fine using SMART.

I upload full core.txt here in case someone can have a look.


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## CyberCr33p (Dec 12, 2019)

Datacenter replaced the server but kept the drives. The server runs now stable for 3 days.


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