On 08/26, Douglas Anderson wrote: > From: Doug Anderson <diand...@chromium.org> > > Dumping registers from other sleeping tasks in KGDB was totally > failing for me. All registers were reported as 0 in many cases. > > The code was using task_pt_regs(task) to try to get other thread > registers. This doesn't appear to be the right place to look. From > my tests, I saw non-zero values in this structure when we were looking > at a kernel thread that had a userspace task associated with it, but > it contained the register values from the userspace task. So even in > the cases where registers weren't reported as 0 we were still not > showing the right thing. > > Instead of using task_pt_regs(task) let's use task_thread_info(task). > This is the same place that is referred to when doing a dump of all > sleeping task stacks (kdb_show_stack() -> show_stack() -> > dump_backtrace() -> unwind_backtrace() -> thread_saved_sp()). > > As further evidence that this is the right thing to do, you can find > the following comment in "gdbstub.c" right before it calls > sleeping_thread_to_gdb_regs(): > Pull stuff saved during switch_to; nothing else is accessible (or > even particularly relevant). This should be enough for a stack > trace. > ...and if you look at switch_to() it only saves r4-r11, sp and lr. > Those are the same registers that I'm getting out of the > task_thread_info(). > > With this change you can use "info thread" to see all tasks in the > kernel and you can switch to other tasks and examine them in gdb. > > Signed-off-by: Doug Anderson <diand...@chromium.org> > Signed-off-by: Douglas Anderson <diand...@chromium.org> > ---
Works for me. Tested-by: Stephen Boyd <sb...@codeurora.org> -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
