> -----Original Message-----
> > My kernel does not support modules -> easier upgrades, just
> compile and
> > edit a symlink than powercycle. its more secure too.
> because I have some
> > users with root rights in their uml`s, so they could in
> theory (if they
> > were smart and evil) compile some of the hostfs stuff as a module...
> Yep, I do that too - and run them in a chroot with selinux, yet I am
> pretty sure there are still some evil things that can be done just
> with /proc/mm...
Agreed.
In fact, one of my production servers developed a rather serious issue
when I upgraded the host kernel from 2.6.13.2 to 2.6.14.2 (both using
SKAS3-v8.2). The host server would "freeze" hard when shutting down the
guest instances (no network, console, etc). The issue disappeared when I
reverted the host back to 2.6.13.2.
Eventually I traced it back to an instance that was still running a
2.6.7 guest kernel. It triggered either during shutdown or within 0-5
seconds after the instance was "killed" (the guest kernel wouldn't exit
cleanly). The issue disappeared once I upgraded it to a more recent
version. Unfortunately, only one of the "freezes" dumped any information
(see below). Every other "freeze" resulted in a non-responsive system
where I had to power-cycle to recover.
So, either SKAS3, the tuntap device, network bridges, or some other host
component associated with UML instances still has some issues.
Tony
Unable to handle kernel NULL pointer dereference at virtual address
00000000
printing eip:
f8be14f4
*pde = 00000000
Oops: 0000 [#1]
SMP
Modules linked in: autofs4 tun ipv6 bridge floppy pcspkr hw_random
i2c_amd8111 generic amd74xx shpchp pci_hotplug ohci_hcd usbcore raid1
md_mod dm_mod rtc w83627hf eeprom lm85 hwmon_vid i2c_isa i2c_amd756
i2c_core tg3 e100 mii psmouse ide_generic ide_disk ide_cd cdrom ide_core
unix
CPU: 1
EIP: 0060:[<f8be14f4>] Not tainted VLI
EFLAGS: 00010287 (2.6.14.2-skas3-v8.2)
EIP is at br_nf_forward_ip+0xa2/0x16a [bridge]
eax: 00000000 ebx: d7b59dc0 ecx: ea4a5380 edx: 00000080
esi: 00000002 edi: 00000002 ebp: f8bdbdb7 esp: e172bcc8
ds: 007b es: 007b ss: 0068
Process linux-2.6.7-02- (pid: 4049, threadinfo=e172a000 task=e99ed550)
Stack: 80000000 c03e7350 c02d44e7 00000002 e172bd58 f8be1334 80000000
ea4a5380
e172bd40 80000000 c03e7350 c02d44e7 00000002 e172bd7c f2641000
efd7e800
f8bdbdb7 00000002 e172bd7c c03e7350 f8bdbdb7 c02d4564 c03e7350
e172bd7c
Call Trace:
[<c02d44e7>] nf_iterate+0x66/0x8a
[<f8be1334>] br_nf_forward_finish+0x0/0x11e [bridge]
[<c02d44e7>] nf_iterate+0x66/0x8a
[<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
[<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
[<c02d4564>] nf_hook_slow+0x59/0x10e
[<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
[<f8bdbefa>] __br_forward+0x63/0x7c [bridge]
[<f8bdbdb7>] br_forward_finish+0x0/0x6b [bridge]
[<f8bdc11b>] br_flood_forward+0x27/0x2c [bridge]
[<f8bdbe97>] __br_forward+0x0/0x7c [bridge]
[<f8bdcb1b>] br_handle_frame_finish+0x11b/0x137 [bridge]
[<f8be094c>] br_nf_pre_routing_finish+0x1a6/0x36b [bridge]
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
[<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
[<c02d4564>] nf_hook_slow+0x59/0x10e
[<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<f8be11a6>] br_nf_pre_routing+0x332/0x457 [bridge]
[<f8be07a6>] br_nf_pre_routing_finish+0x0/0x36b [bridge]
[<c02d44e7>] nf_iterate+0x66/0x8a
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<c02d4564>] nf_hook_slow+0x59/0x10e
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<f8bdccec>] br_handle_frame+0x1b5/0x229 [bridge]
[<f8bdca00>] br_handle_frame_finish+0x0/0x137 [bridge]
[<c027e6e9>] netif_receive_skb+0x1af/0x334
[<f8a74bf5>] e100_poll+0x1cf/0x70c [e100]
[<c027ea36>] net_rx_action+0xc1/0x197
[<c01206a2>] __do_softirq+0x72/0xdd
[<c0120740>] do_softirq+0x33/0x35
[<c0104e7e>] do_IRQ+0x1e/0x24
[<c0103772>] common_interrupt+0x1a/0x20
Code: c1 e2 06 8d 82 90 71 3e c0 3b 82 90 71 3e c0 74 58 c7 44 24 18 00
00 00 80 c7 44 24 14 34 13 be f8 8b 44 24 3c 8b 80 ec 02 00 00 <8b> 00
8b 40 0c 89 44 24 10 8b 44 24 38 8b 80 ec 02 00 00 8b 00
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