Re: [Crash-utility] Re: Problem with using crash 4.0-2.21 on ppc

Haren Myneni wrote: > > > crash-utility-bounces(a)redhat.com wrote on 02/22/2006 07:31:43 AM: > > > Rachita Kothiyal wrote: > > > > > > > > > Rachita Kothiyal wrote: > > > > > > > > > > > > > > This happens in get_idle_threads() when perusing the runqueues > array, > > > > where each per-cpu runqueue data structure contains a pointer to the > > > > idle (swapper) task for that CPU. Now, this process requires > that the > > > > per-cpu address manipulations are working correctly in order to > find the > > > > each cpu's runqueue data structure. It looks like the ppc64 change > > > > for per-cpu data accesses is suspect here: > > > > > > > > > Fix to recognize post-2.6.15 ppc64 kernels moving the > per_cpu_offsets > > > > > to the "paca" structure. Without this patch, crash fails with the > > > > > following error messages: "crash: cannot determine idle task > addresses > > > > > from init_tasks[] or runqueues[]" and "crash: cannot resolve > > > > > init_task_union". (pbadari(a)us.ibm.com) > > > > > > > > > > Right, but I thought this patch fixed this problem. > > > (I am using crash-4.0-2.21, and it includes this patch) > > > > Right -- me too... ;-) > > Badari tested his patch on live system. He can give more information > anyway. > > However, I used his patch for testing PPC64 vmcore before I post my > patch. Did not see any issue when invoking crash tool. Tested on > 2.6.16-rc2-gi9. > > I will also verify if I have the same vmcore. > > Thanks > Haren > Dave, I used Badari's patch (first version) for my testing on PPC64 kdump vmcore. Later, this patch was changed to use paca[CPU#].hw_cpu_id to determine whether the CPU exists (CPU hotplug case). The reason it failed on vmcore is, when the kdump boot happens, this hw_cpu_id is set to -1 for secondary cpus when they stopped. Hence, not setting per_cpu_offset for these CPUs and causing this issue. Instead of looking for hw_cpu_id, this patch will look for the corresponding data_offset. If 0, means CPU does not exists. Rachita, please let us know if still an issue. Badari, is there any issue with this patch?