Re: [PATCH 3/3] x86/dumpstack: Add show_stack_regs() and use it

[Andy Lutomirski]

On Fri, Jun 24, 2016 at 1:30 AM, Borislav Petkov <bp@xxxxxxxxx> wrote:
> From: Borislav Petkov <bp@xxxxxxx>
>
> Add a helper to dump supplied pt_regs and use it in the MSR exception
> handling code to have precise stack traces pointing to the actual
> function causing the MSR access exception and not the stack frame of the
> exception handler itself.
>
> The new output looks like this:
>
>  unchecked MSR access error: RDMSR from 0xdeadbeef at rIP: 0xffffffff8102ddb6 (early_init_intel+0x16/0x3a0)
>   00000000756e6547 ffffffff81c03f68 ffffffff81dd0940 ffffffff81c03f10
>   ffffffff81d42e65 0000000001000000 ffffffff81c03f58 ffffffff81d3e5a3
>   0000800000000000 ffffffff81800080 ffffffffffffffff 0000000000000000
>  Call Trace:
>   [<ffffffff81d42e65>] early_cpu_init+0xe7/0x136
>   [<ffffffff81d3e5a3>] setup_arch+0xa5/0x9df
>   [<ffffffff81d38bb9>] start_kernel+0x9f/0x43a
>   [<ffffffff81d38294>] x86_64_start_reservations+0x2f/0x31
>   [<ffffffff81d383fe>] x86_64_start_kernel+0x168/0x176

Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>