RE: Kernel trap when booting inside VirtualBox

From: Paul Wootton <paulw_at_fisheyehq.com>
Date: Tue, 12 Apr 2016 23:00:57 +0100
On Tue, Apr 12, 2016 at 02:02PM, Paul Wootton wrote:
>On Tue, Apr 12, 2016 at 08:56AM, Konstantin Belousov wrote:
>>Anyway, please do 'kgdb kernel.debug' for your HEAD kernel, and
>>send me the disassemble of the native_lapic_setup function.
>
>"
>Dump of assembler code for function native_lapic_setup:
>0xffffffff80fd1320 <native_lapic_setup+0>:      add    %al,(%rax)
>0xffffffff80fd1322 <native_lapic_setup+2>:      add    %al,(%rax)
>0xffffffff80fd1324 <native_lapic_setup+4>:      add    %al,(%rax)
>0xffffffff80fd1326 <native_lapic_setup+6>:      add    %al,(%rax)
>0xffffffff80fd1328 <native_lapic_setup+8>:      add    %al,(%rax)
>...
>...
>0xffffffff80fd1880 <native_lapic_setup+1376>:   add    %al,(%rax)
>0xffffffff80fd1882 <native_lapic_setup+1378>:   add    %al,(%rax)
>0xffffffff80fd1884 <native_lapic_setup+1380>:   add    %al,(%rax)
>0xffffffff80fd1886 <native_lapic_setup+1382>:   add    %al,(%rax)
>End of assembler dump
>"
>Every line is the same instruction, add %al,(%rax)
>
>I downloaded an ISO of r294499 and that booted correctly inside VBox.
>I SVNed down to r294499, compiled and that did not boot. Did a disassembley
and it's the same as above.
>I downloaded an ISO of r297692 and that booted correctly.
>
>So it's got to be either my kernel conf or my enviroment
>
>Im going to try and compile a generic kernel and see if that works

With the help of Konstantin, I have got a proper disassembly.

I have recompiled a few times so my new panic is
instruction pointer     = 0x20:0xffffffff80fed2d9
stack pointer           = 0x28:0xffffffff824d89c0
frame pointer           = 0x28:0xffffffff824d8a40
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         = 0 (swapper)
[ thread pid 0 tid 100000 ]
Stopped at      native_lapic_setup+0x99:         lesl    %edx,%esp

and a disassembly gives
0xffffffff80fed2d9 <native_lapic_setup+153>:    (bad)  0x99 == 153

Now to figure out why I am making bad binaries.
Ive not seen any issues yet with the world, so its not as if every binary I
make is bad




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Received on Tue Apr 12 2016 - 21:20:29 UTC

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