----- "Dave Anderson" <anderson(a)redhat.com&gt; wrote: > ----- "Daisuke HATAYAMA" <d.hatayama(a)jp.fujitsu.com&gt; wrote: > > > Hi, all. > > > > I have a question on the implementation of > get_netdump_regs_x86_64(). > > > > Currently, in order to get register values for active tasks, only > > panic task makes use of note information. On the other hand, other > > active tasks search stack frame for registers saved at nmi > > switch. However, crash dump contains the note information for every > > CPUs, so I think it uncessary to search stack frame. > > Originally it was done that way because the code was written for > netdump-generated dumpfiles, which only generated note information > for the panic task. But if I'm not mistaken, given that recent > kernels do not store debuginfo data for the user_regs_struct, it > almost always falls through into x86_64_get_stack_frame(). I take that back -- when it's not in the debuginfo, it hardwires the user_regs_struct data structure information. That being the case, I don't remember why it is restricted to the panic task, but it had to have been put in place based upon actual dumpfiles where it didn't work correctly for a non-panic task. If I get the time, I'll remove the restriction and run it on my set of stashed dumpfile examples to see if I can be more specific.

Anyway, good question -- sorry for such a weak answer...