[uml-user] segv at halt

[Anders K. <and...@me...>]

Hello list,

Previous e-mail detailed two problems I have found. Here is the second
one in more detail. UML boots using hostfs for the root_fs directory
which contains the installed system. ubd1 is a swap file, 16MB in
size. The UML is started with the debug option and once I have given
the continue command in gdb, it boots quite happily. I log in and
issue the 'poweroff' command which shuts the system down. I seems to
work quite happily, killing all processes, turning off swap,
remounting filesystems read-only then trying to halt the system.
The debugger kicks in and I get this backtrace from it.

(gdb) bt
#0  panic (fmt=3D0x10121d20 "Kernel mode fault at addr 0x%lx, ip 0x%lx")
    at panic.c:54
#1  0x100a2e7d in segv (address=3D1515870882, ip=3D268721935, is_write=3D0,=
=20
    is_user=3D0) at trap_kern.c:54
#2  0x100a384b in segv_handler (sig=3D11, sc=3D0x50f23998, usermode=3D0)
    at trap_user.c:303
#3  0x100a3928 in sig_handler (sig=3D11) at trap_user.c:342
#4  <signal handler called>
#5  proc_kill_inodes (de=3D0x500f1dc4) at generic.c:389
#6  0x10046405 in remove_proc_entry (name=3D0x1011f989 "max_dgram_qlen",=20
    parent=3D0x500f1d3c) at generic.c:573
#7  0x1001029e in unregister_proc_table (table=3D0x1013caec, root=3D0x500f1=
d3c)
    at sysctl.c:671
#8  0x1001027a in unregister_proc_table (table=3D0x1013cb44, root=3D0x50056=
c0c)
    at sysctl.c:659
#9  0x1001027a in unregister_proc_table (table=3D0x1013cb9c, root=3D0x5004f=
dec)
    at sysctl.c:659
#10 0x1001010a in unregister_sysctl_table (header=3D0x500572bc) at sysctl.c=
:585
#11 0x10098998 in unix_sysctl_unregister () at sysctl_net_unix.c:43
#12 0x10103749 in af_unix_exit () at af_unix.c:1882
#13 0x100a60f4 in do_exitcalls () at process_kern.c:788
#14 0x100a0ee0 in machine_power_off () at reboot.c:34
#15 0x100154e6 in sys_reboot (magic1=3D-18751827, magic2=3D672274793,=20
    cmd=3D1126301404, arg=3D0x8049500) at sys.c:309
#16 0x100a1ce5 in execute_syscall (regs=3D{regs =3D {4276215469, 672274793,=
=20
        1126301404, 134518016, 4276215469, 3212836180, 4294967258, 43, 43, =
0,=20
        0, 88, 1074622251, 35, 534, 3212836152, 43}}) at syscall_kern.c:348
#17 0x100a1e0a in syscall_handler (unused=3D0x0) at syscall_user.c:73

I then run a few other commands (from memory and the trouble shooting
UML web page).

(gdb) info symbol 0x100a2e7d
segv + 317 in section .text
(gdb) info symbol 0x100a384b
segv_handler + 139 in section .text
(gdb) info symbol 0x100a3928
sig_handler + 76 in section .text


If there is anything else required, give me a shout as I can reproduce
this very easily.

Regards,

--=20
        Anders Karlsson                     Mean Solutions Ltd.
e-mail: and...@me...   Mobile: +44-7711-876270

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