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

Rachita Kothiyal wrote: > Hi > > I tried crash 4.0-2.21 on a 2.6.16-rc4 kernel on a ppc64 > machine(Power5). Trying to analyse vmcore(from kdump) gave me > the following error: > > crash: pglist_data.node_mem_map structure member does not exist. > crash: certain memory-related commands will fail or display invalid data This is to be expected on a CONFIG_SPARSEMEM kernel: > If pglist_data.node_mem_map structure member does not exist, as in a > ppc64 kernel built with CONFIG_SPARSEMEM, print an init-time warning > message instead of failing with "crash: invalid structure member > offset: pglist_data.node_mem_map" message. (haren(a)us.ibm.com, > anderson(a)redhat.com)

> crash: cannot determine idle task addresses from init_tasks[] or runqueues[] > crash: cannot resolve "init_task_union" > 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)

> > But I was able to run it ok on a live system. > Same kernel? I have no idea why there would be a difference between live and vmcore.