On Mon, 2005-10-31 at 17:24 -0500, Dave Anderson wrote:
> > There is no simple way to add #if KERNEL_VERSION > 2.6.10
> > in the header file and leave the hardcoded values there ?
>
>
> THIS_KERNEL_VERSION is based upon crash internal data variables in
> the
> kernel_table data structure that get initialized in kernel_init
> (PRE_GDB)
> based upon the contents of the kernel's "system_utsname" data
> structure
> read from memory or the dumpfile.
>
> I was mistaken in using the value of "_stext" as the qualifier,
> though,
> since the __START_KERNEL_map value of 0xffffffff80000000 is still the
> same.
> But there must be *some* difference in the symbol list that can be
> used
> to determine which set of address values to use. It could even be
> just
> the *existence* of some new kernel variable introduced as part of the
> change to the new scheme. Doing an "nm -Bn" on the old and new
> vmlinux files should yield something obvious.
Okay. I will look around :)
> >
> > bt -t seems to better.
> >
> > crash> bt 3144
> > PID: 3144 TASK: ffff81011dd1e100 CPU: 0 COMMAND: "mingetty"
> > #0 [ffff81011d6b9c68] schedule at ffffffff803b12b3
> > RIP: 000000377c7b85b2 RSP: 00007fffff87a110 RFLAGS: 00010246
> > RAX: 0000000000000000 RBX: ffffffff8010dc26 RCX: 00007fffff87a7b0
> > RDX: 0000000000000001 RSI: 00007fffff87a8c7 RDI: 0000000000000000
> > RBP: 00007fffff87aca0 R8: 00002aaaaaac9b00 R9: 0000000000000000
> > R10: 0000000000000001 R11: 0000000000000246 R12: 00007fffff87a900
> > R13: 0000000000502d20 R14: 0000000000000000 R15: 000000007c92d8c0
> > ORIG_RAX: 0000000000000000 CS: 0033 SS: 002b
> > crash> bt -t 3144
> > PID: 3144 TASK: ffff81011dd1e100 CPU: 0 COMMAND: "mingetty"
> > START: thread_return (schedule) at ffffffff803b12b3
> > [ffff81011d6b9d10] do_con_write at ffffffff802689da
> > [ffff81011d6b9d80] schedule_timeout at ffffffff803b1e4e
> > [ffff81011d6b9db0] _spin_lock_irqsave at ffffffff803b28ce
> > [ffff81011d6b9dc0] add_wait_queue at ffffffff8014cf5c
> > [ffff81011d6b9de0] read_chan at ffffffff8025d1f7
> > [ffff81011d6b9e48] default_wake_function at ffffffff80130c90
> > [ffff81011d6b9e78] default_wake_function at ffffffff80130c90
> > [ffff81011d6b9e90] tty_ldisc_deref at ffffffff802571c4
> > [ffff81011d6b9ed0] tty_read at ffffffff802575ee
> > [ffff81011d6b9f10] vfs_read at ffffffff80183a46
> > [ffff81011d6b9f40] sys_read at ffffffff80183e03
> > [ffff81011d6b9f80] system_call at ffffffff8010dc26
> > RIP: 000000377c7b85b2 RSP: 00007fffff87a110 RFLAGS: 00010246
> > RAX: 0000000000000000 RBX: ffffffff8010dc26 RCX: 00007fffff87a7b0
> > RDX: 0000000000000001 RSI: 00007fffff87a8c7 RDI: 0000000000000000
> > RBP: 00007fffff87aca0 R8: 00002aaaaaac9b00 R9: 0000000000000000
> > R10: 0000000000000001 R11: 0000000000000246 R12: 00007fffff87a900
> > R13: 0000000000502d20 R14: 0000000000000000 R15: 000000007c92d8c0
> > ORIG_RAX: 0000000000000000 CS: 0033 SS: 002b
> > crash>
> >
>
>
> I still don't understand what happens in
> x86_64_low_budget_back_trace_cmd()
> that causes the "bt" command to skip from the starting point in
> schedule()
> to the end, where it dumps the user-mode entry exception frame,
> unless
> the rsp has been bumped too high by the time it gets to this point:
>
> /*
> * Walk the process stack.
> */
> for (i = (rsp - bt->stackbase)/sizeof(ulong);
> !done && (rsp < bt->stacktop); i++, rsp += sizeof(ulong))
> {
>
> ...and that conceivably may have something to do with the exception
> stack
> problem. It's hard to say without being there...
I added lots of debug code while playing with it and forgot to
clean it up properly. All problems went away after a cleanup.
(stack trace issues, exception stack issues etc..)
Thanks,
Badari
