[PATCH v2] xmon: Setup xmon debugger hooks when first break-point is set

[Balbir Singh]

On Mon, Mar 5, 2018 at 4:30 AM, Vaibhav Jain <vaibhav at linux.vnet.ibm.com> wrote:
> Presently sysrq key for xmon('x') is registered during kernel init
> irrespective of the value of kernel param 'xmon'. Thus xmon is enabled
> even if 'xmon=off' is passed on the kernel command line. However this
> doesn't enable the kernel debugger hooks needed for instruction or data
> breakpoints. Thus when a break-point is hit with xmon=off a kernel oops
> of the form below is reported:
>
> Oops: Exception in kernel mode, sig: 5 [#1]
> < snip >
> Trace/breakpoint trap
>
> To fix this the patch checks and enables debugger hooks when an
> instruction or data break-point is set via xmon console.
>
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>
> ---
Reviewed-by: Balbir Singh <bsingharora at gmail.com>