• Heiko Carstens's avatar
    s390/dumpstack: merge all four stack tracers · 758d39eb
    Heiko Carstens authored
    We have four different stack tracers of which three had bugs. So it's
    time to merge them to a single stack tracer which allows to specify a
    call back function which will be called for each step.
    This patch changes behavior a bit:
    - the "nosched" and "in_sched_functions" check within
      save_stack_trace_tsk did work only for the last stack frame within a
      context. Now it considers the check for each stack frame like it
    - both the oprofile variant and the perf_events variant did save a
      return address twice if a zero back chain was detected, which
      indicates an interrupt frame. The new dump_trace function will call
      the oprofile and perf_events backends with the psw address that is
      contained within the corresponding pt_regs structure instead.
    - the original show_trace and save_context_stack functions did already
      use the psw address of the pt_regs structure if a zero back chain
      was detected. However now we ignore the psw address if it is a user
      space address. After all we trace the kernel stack and not the user
      space stack. This way we also get rid of the garbage user space
      address in case of warnings and / or panic call traces.
    So this should make life easier since now there is only one stack
    tracer left which we can break.
    Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
dumpstack.c 5.58 KB