• Chris Metcalf's avatar
    tile: improve stack backtrace · 47ad7b9b
    Chris Metcalf authored
    This commit fixes a number of issues with the tile backtrace code.
    
    - Don't try to identify userspace shared object or executable paths
      if we are doing a backtrace from an interrupt; it's not legal,
      and also unlikely to be interesting.  Likewise, don't try to do
      it for other address spaces, since d_path() assumes it is being
      called in "current" context.
    
    - Move "in_backtrace" from thread_struct to thread_info.
      This way we can access it even if our stack thread_info has been
      clobbered, which makes backtracing more robust.
    
    - Avoid using "current" directly when testing for is_sigreturn().
      Since "current" may be corrupt, we're better off using kbt->task
      explicitly to look up the vdso_base for the current task.
      Conveniently, this simplifies the internal APIs (we only need
      one is_sigreturn() function now).
    
    - Avoid bogus "Odd fault" warning when pc/sp/ex1 are all zero,
      as is true for kernel threads above the last frame.
    
    - Hook into Tejun Heo's dump_stack() framework in lib/dump_stack.c.
    
    - Write last entry in save_stack_trace() as ULONG_MAX, not zero,
      since ftrace (at least) relies on finding that marker.
    
    - Implement save_stack_trace_regs() and save_strack_trace_user(),
      and set CONFIG_USER_STACKTRACE_SUPPORT.
    Signed-off-by: default avatarChris Metcalf <cmetcalf@ezchip.com>
    47ad7b9b
thread_info.h 6.21 KB