[User-mode-linux-devel] Kernel panic in 2.4.0-test8-cvs-000913

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Good day, all,
	I was doing the usual wget-pages-from-the-host-to-the-uml-squid
and ping-flood-the-host-from-uml and got the following on the console:

bash# Kernel panic: Kernel mode fault at addr 0x0, ip 0x1000160c
Message from syslogd@uml-test at Wed Sep 13 16:26:18 2000 ...
uml-test kernel: Kernel panic: Kernel mode fault at addr 0x0, ip 0x1000160c
Scheduling in interrupt
kernel BUG at sched.c:698!

	From sched.c:
scheduling_in_interrupt:
        printk("Scheduling in interrupt\n");
        BUG();
        return;
}

	With the howto as a guide, I tried to get some relevant state with
gdb:

[wstearns@sparrow rh6.2]$ gdb linux-2.4.0-test8-cvs-000913
GNU gdb 19991004
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for
details.
This GDB was configured as "i386-redhat-linux"...
(gdb) att 9941
Attaching to program: /home/wstearns/uml/rh6.2/linux-2.4.0-test8-cvs-000913, Pid 9941
0x100a9a89 in __wait4 ()

(gdb) p current_task.pid
$1 = 544

(gdb) p current_task.comm
$2 = "piD'Pd'P\000\000\000\000L"

(gdb) p current_task.prev_task.comm
$3 = "bash\000\000ty\000\000\000\000\000\000\000"

(gdb) p current_task.thread
$4 = {extern_pid = 1344791268, tracing = 0, forking = 269067394,
kernel_stack = 1344791140, real_mm = 0x50017dc0, starting_exec =
269612136, signal = {
    signal = 269612108, sp = 301999616, handler = 0}, npending = 0,
saved_sigs = {sig = {1344791180, 1344791468}}, nsyscalls = 0, process_regs
= {regs = {1,
      1344794484, 0, 8, 1, 1344794324, 0, 43, 43, 0, 0, 1344791364,
269105191, 35, 582, 1344794300, 43}}, syscall_regs = {regs = {1344791256,
269067201,
      1344791268, 1344791556, 0, 1344791276, 269067201, 1344791300, 14,
1344791556, 1344791428, 1344791684, 269067394, 1344791300, 1354079040, 0,
269834784}},
  syscall_stack = 0x12002600, syscall_stack_size = 0, altstack_regs =
{regs = {0 <repeats 17 times>}}, altstack = 0x0, altstack_size = 0, cr2 =
0, err = 0,
  check_sigs = 0, restore_state = 0, mm_changes = 0, fault_addr = 0x0,
syscall = {id = 0, args = {0, 0, 0, 0, 0, 0}, have_result = 0, result = 0,
again = 0},
  request = {op = 0, u = {exec = {ip = 0, sp = 0}, fork = {task = 0x0,
tramp_stack = 0, sp = 0}, cswitch = {to = 0x0, from = 0x0}, thread = {proc
= 0, arg = 0x0,
        flags = 0, new_pid = 0, new_task = 0x0, cpu = 0}, fork_finish =
{stack = 0, regs = {regs = {0 <repeats 17 times>}}, from = 0x0}, cb =
{proc = 0,
        arg = 0x0}}}}
(gdb) p current_task.prev_task.thread
$5 = {extern_pid = 13533, tracing = 0, forking = 0, kernel_stack =
1354440704, real_mm = 0x50e96780, starting_exec = 0, signal = {signal =
17, sp = 0,
    handler = 134594960}, npending = 0, saved_sigs = {sig = {0, 0}},
nsyscalls = 767, process_regs = {regs = {0, 3212833995, 1, 3212833995, 1,
3212833996,
      4294967258, 43, 43, 0, 0, 3, 1074530996, 35, 646, 3212833964, 43}},
syscall_regs = {regs = {13533, 19, 13533, 1354564220, 0, 1354448144, 0,
43, 43, 0, 0, 37,
      269105313, 35, 515, 1354448072, 43}}, syscall_stack = 0x5079e000,
syscall_stack_size = 824, altstack_regs = {regs = {0 <repeats 17 times>}},
altstack = 0x0,
  altstack_size = 0, cr2 = 0, err = 0, check_sigs = 0, restore_state = 0,
mm_changes = 0, fault_addr = 0x0, syscall = {id = 3, args = {0,
3212833995, 1,
      3212833995, 1, 3212833996}, have_result = 0, result = 6, again = 0},
request = {op = 0, u = {exec = {ip = 1347805184, sp = 1347026944}, fork =
{
        task = 0x5055e000, tramp_stack = 1347026944, sp = 0}, cswitch =
{to = 0x5055e000, from = 0x504a0000}, thread = {proc = 0x5055e000, arg =
0x504a0000,
        flags = 0, new_pid = -1082144096, new_task = 0x40145220, cpu =
-1082138916}, fork_finish = {stack = 1347805184, regs = {regs =
{1347026944, 0, 3212823200,
            1075073568, 3212828380, 3212827996, 0, 43, 43, 0, 0, 2,
1074678903, 35, 514, 3212823816, 43}}, from = 0x50afc000}, cb = {proc =
0x5055e000,
        arg = 0x504a0000}}}}
(gdb)

	I still have the uml running if you need more info.
	Cheers,
	- Bill

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	The man who sets out to carry a cat by its tail learns something
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	-- Mark Twain.
(Courtesy of Thierry GUINET <T.G...@na...>)
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William Stearns (wst...@po...).  Mason, Buildkernel, named2hosts, 
and ipfwadm2ipchains are at:                http://www.pobox.com/~wstearns
LinuxMonth; articles for Linux Enthusiasts! http://www.linuxmonth.com
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