Re: [PATCH] x86, add hypervisor name to dump_stack()

From: Ingo Molnar
Date: Wed Oct 24 2012 - 05:49:40 EST



* Prarit Bhargava <prarit@xxxxxxxxxx> wrote:

> Debugging crash, panics, stack trace WARN_ONs, etc., from both virtual and
> bare-metal boots can get difficult very quickly. While there are ways to
> decipher the output and determine if the output is from a virtual guest,
> the in-kernel hypervisors now have a single registration point and set
> x86_hyper. We can use this to output a single extra line on virtual
> machines that indicates the hypervisor type.
>
> Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
> Cc: Avi Kivity <avi@xxxxxxxxxx>
> Cc: Gleb Natapov <gleb@xxxxxxxxxx>
> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Marcelo Tostatti <mtosatti@xxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx
> Cc: x86@xxxxxxxxxx
> ---
> arch/x86/kernel/dumpstack.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
> index ae42418b..75a635e 100644
> --- a/arch/x86/kernel/dumpstack.c
> +++ b/arch/x86/kernel/dumpstack.c
> @@ -17,6 +17,7 @@
> #include <linux/sysfs.h>
>
> #include <asm/stacktrace.h>
> +#include <asm/hypervisor.h>
>
>
> int panic_on_unrecovered_nmi;
> @@ -193,6 +194,8 @@ void dump_stack(void)
> init_utsname()->release,
> (int)strcspn(init_utsname()->version, " "),
> init_utsname()->version);
> + if (x86_hyper && x86_hyper->name)
> + printk("Hypervisor: %s\n", x86_hyper->name);
> show_trace(NULL, NULL, &stack, bp);

Looks useful, but please don't waste a full new line on it but
embedd it in the already existing status line that prints
details like release and version.

Thanks,

Ingo
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