On Thu, Aug 1, 2013 at 9:55 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: > On 08/01/2013 07:49 AM, Vijay Kilari wrote: >> On Wed, Jul 31, 2013 at 10:44 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: >>> On 07/31/2013 05:37 AM, Vijay Kilari wrote: >>>> On Tue, Jul 30, 2013 at 10:29 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: >>>>> On 07/30/2013 04:37 AM, Vijay Kilari wrote: >>>>>> On Fri, Jul 26, 2013 at 10:38 PM, Stephen Warren <swarren at wwwdotorg.org> wrote: >>>>> ... >>>>>>> Does a kernel that's used as the crash kernel guarantee: >>>>>>> >>>>>>> * Never to re-use the memory that was used by the previous kernel, so >>>>>>> that the spin loop code/data won't be corrupted, ever, no matter how >>>>>>> long the crash recovery kernel runs. >>>>>>> >>>>>>> * Not use SMP, so there's never a need to re-activate the non-boot CPUs, >>>>>>> which might not work if they aren't truly disabled but rather just >>>>>>> running a pin loop? >>>>>> >>>>>> From cat /proc/iomem, normal kernel is executed from (0x80xxxxxx) with crash >>>>>> kernel reserved 64M at 0xa0000000 >>>>>> >>>>>> 80000000-bfffffff : System RAM >>>>>> 80008000-805aeddf : Kernel code >>>>>> 805e2000-8063e427 : Kernel data >>>>>> a0000000-a3ffffff : Crash kernel >>>>>> >>>>>> crash kernel is loaded to reserved memory location and is executed from there. >>>>>> I could confirm this from /proc/iomem when crash kernel is running >>>>>> >>>>>> a0000000-a3efffff : System RAM >>>>>> a0008000-a05aeddf : Kernel code >>>>>> a05e2000-a063e427 : Kernel data >>>>> >>>>> OK, but in the crash dump kernel, is 80008000..8063e427 reserved as >>>>> well, which would guarantee that the spin loop being executed by the >>>>> non-crash CPUs won't be corrupted? >>>> >>>> The crash dump kernel runs from reserved memory area (0xa0000000 - 0xa3effffff). >>>> So it should not corrupt the memory area of original kernel that was running >>>> at 0x80000000,where other CPU's are in spin loop. >>> >>> What about dynamic allocations? >> >> IMHO, it is the kdump functionality to ensure that it won't corrupt >> original kernel's dynamic allocations > > OK, if there are explicit measure to assure this already, then there's > no issue. Hi Will, Can you please consider this patch? Thanks & Regards Vijay
