Don't Panic - how do I investigate a kernel panic?

[Kris Kennaway]

On Tue, Apr 12, 2005 at 11:19:02PM +0200, Erik N?rgaard wrote:
> Hi,
> 
> I have a 5.3-STABLE which was stable untill last friday. Since then I 
> experience irregular panics, with uptimes between 25 secs and 16 hours.
> 
> In most cases I got a fatal trap 12, the last panic was simply "panic: 
> sbdrop".
> 
> I had 5.3p5 but upgraded to 5.3p8 after the first panics. After the last 
> trap 12, I replaced my custom kernel with a fresh built GENERIC, as I 
> thought it might be easier to investigate.
> 
> I have experienced trap 12 before startup completed and after shutdown 
> unmounted all disks. So, it seems not to be triggered by network events.
> 
> However, about the same time as the first panic and since then, I have 
> experienced an unusually high amount of ilicit mail delivery attempts to 
> adresses like <random_chars>@mydomain.com - not the amount I would 
> expect could cause a crash though, my connection is far to thin for that.
> 
> Following the kernel panic faq:
> 
> Fatal trap 12: Page fault while in kernel mode
> Fault virtual address   = 0xc
> Fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xc053d638
> stack pointer           = 0x10:0xcb4ddaec
> frame pointer           = 0x10:0xcb4ddaf8
> code segment            = base 0x0, limit 0xffff, type 0x1b
>                         = DPL 0, pres 1, def32 1, gran 1
> processor eflags        = interrupt enabled, resume, IOPL=0
> current process         = 28 (swi1:net)
> trap number             = 12
> panic: page fault
> 
> # nm -n /boot/kernel/kernel | grep  c053d6
> c053d610 T m_copydata
> c053d670 T m_dup
> 
> Note: This was the same error for both the custom p5 and p8 kernels.
> 
> The sbdrop panic happened with the GENERIC kernel.
> 
> What does sbdrop mean? Is this a simple disk I/O or hardware error? How 
> do I get on from here?

Upgrade to 5.4, I believe this was fixed some time ago.  If you still
see it, then follow the directions in the developers' handbook about
compiling your kernel with debugging symbols and obtaining a
traceback.

Kris
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