Hi ,

I am working on MIPS64 processor , When I am trying to make the box up with PPP connection, I am facing random kernel panics. All panics says description "unhandled kernel memory access". I am copying some sample crashes here. Any pointers to debug would be very much helpful.

All the below crashes happens only when PPP connection is made, I mean when ppp interface is going up/down.

Unhandled kernel unaligned access[#1]:
Cpu 0
$ 0 : 0000000000000000 0000000000000004 0000000000000000 0000000000000000
$ 4 : ffffffff81112124 ffffffffdc830008 ffffffff813ce120 ffffffff813ce11c
$ 8 : 1400000100000008 0000000000000000 ffffffff814c0000 ffffffff814f0000
$12 : 000000001010ffe1 000000001000001e ffffffff814f0000 ffffffff82a30000
$16 : a800000009747a10 a800000008cc0800 0000000000000000 a80000000d368c00
$20 : a800000008cc0800 0000000000000000 a80000000d368c00 a80000000d368c00
$24 : 0000000000000007 0000000000000000
$28 : a800000009744000 a8000000097479e0 a800000009747c90 ffffffff8110a600
Hi : 0000000000000090
Lo : e5604189374bc754
epc : ffffffff8111213c do_ade+0x3dc/0x4e0 Tainted: P
ra : ffffffff8110a600 handle_adel_int+0x2c/0x4c
Status: 1010ffe3 KX SX UX KERNEL EXL IE
Cause : 00800010
BadVA : 1400000100000008
PrId : 000d0202
Modules linked in: ifDev mii n_hdlc vipsec sip xcalibur bridge endChant umi
ethernet
Process pppd (pid: 4504, threadinfo=a800000009744000, task=a80000000bae9340)
Stack : a80000000d368c00 a800000008cc0800 a80000000a204200 a80000000d368c00
ffffffff8110a600 ffffffff82a50000 0000000000000000 0000000000000004
ffffffffe0000001 0000000000000000 1400000100000000 00000000e0000001
ffffffff814682c8 000000000000008c 0000000000000000 a800000008aa4400
ffffffff814c0000 ffffffff814f0000 0000000000000000 ffffffff814c0000
ffffffff814f0000 ffffffff82a30000 a80000000d368c00 a800000008cc0800
a80000000a204200 a80000000d368c00 a800000008cc0800 0000000000000000
a80000000d368c00 a80000000d368c00 0000000000000007 0000000000000000
00000000386d43d7 00000000000572d0 a800000009744000 a800000009747b70
a800000009747c90 ffffffff813ce100 000000001010ffe3 0000000000000090
...
Call Trace:
[<ffffffff8110a600>] handle_adel_int+0x2c/0x4c
[<ffffffff813ce100>] ip_mc_inc_group+0x178/0x380
[<ffffffff813ce11c>] ip_mc_inc_group+0x194/0x380
[<ffffffff8137dc88>] netlink_broadcast+0x240/0x5c8
[<ffffffff813ce81c>] ip_mc_up+0x5c/0x110
[<ffffffff813c7210>] inetdev_event+0x240/0x438
[<ffffffff811458e8>] notifier_call_chain+0x50/0x80
[<ffffffff81360424>] dev_open+0xe4/0xf0
[<ffffffff8135dd70>] dev_change_flags+0x118/0x170
[<ffffffff813c7dec>] devinet_ioctl+0x654/0x888
[<ffffffff813c78bc>] devinet_ioctl+0x124/0x888
[<ffffffff81194360>] sys_newstat+0x20/0x48
[<ffffffff81352f6c>] sock_ioctl+0x184/0x448
[<ffffffff8119e3f0>] do_ioctl+0x30/0x88
[<ffffffff8119c7a4>] __user_walk_fd+0x74/0xa0
[<ffffffff8119e4c4>] vfs_ioctl+0x7c/0x3b0
[<ffffffff8119e844>] sys_ioctl+0x4c/0xb8
[<ffffffff811bef18>] dev_ifsioc+0x78/0x388
[<ffffffff81194360>] sys_newstat+0x20/0x48
[<ffffffff811bc584>] compat_sys_ioctl+0x194/0x3d8
[<ffffffff8111beb4>] handle_sysn32+0x54/0xa4
[<ffffffff81273294>] memset_partial+0x30/0x60
[<ffffffff8110e460>] old_mmap+0x0/0x150


Code: 00431024 1440ff7e 00000000 <69040000> 6d040007 24020000 1440ffbb 7ca22403 084447f6
Kernel panic - not syncing: Aiee, killing interrupt handler!

Unhandled kernel unaligned access[#1]:
Cpu 0
$ 0 : 0000000000000000 0000000000000004 0000000000000000 0000000000000000
$ 4 : ffffffff81111eb4 ffffffff8c820008 ffffffff81365868 ffffffff81365864
$ 8 : fffffffd00000008 0000000000000000 ffffffff82770000 ffffffff82770000
$12 : 000000001010ffe0 000000001000001e ffffffff82770000 a80000000b266680
$16 : a80000000844fd50 0000000000000000 0000000000000000 ffffffff82770000
$20 : 0000000000000001 ffffffff82774690 ffffffff82770000 0000000000000000
$24 : ffffffff82770000 ffffffff82770000
$28 : a80000000844c000 a80000000844fd20 0000000000000000 ffffffff8110a538
Hi : 0000000000000000
Lo : 0000000000000008
epc : ffffffff81111ecc do_ade+0x32c/0x4e0 Tainted: P
ra : ffffffff8110a538 handle_adel_int+0x28/0x30
Status: 1010ffe2 KX SX UX KERNEL EXL
Cause : 00800010
BadVA : fffffffd00000008
PrId : 000d0202
Modules linked in: ifDev mii n_hdlc vipsec sip xcalibur bridge endChant umi
Process ksoftirqd/0 (pid: 2, threadinfo=a80000000844c000, task=a80000000844a9c0)
Stack : a80000000e637980 0000000000000000 0000000000000000 ffffffff82770000
ffffffff8110a538 ffffffff8150a6f0 0000000000000000 0000000000000004
0000000000000000 0000000000000001 fffffffd00000000 0000000000000000
ffffffff82774700 000000000000001f a80000000a060b00 ffffffff82770000
ffffffff82770000 ffffffff82770000 a80000000a4f8680 ffffffff81510000
ffffffff82770000 a80000000b266680 a80000000e637980 0000000000000000
0000000000000000 ffffffff82770000 0000000000000001 ffffffff82774690
ffffffff82770000 0000000000000000 ffffffff82770000 ffffffff82770000
00000000000000d8 a80000000d938c00 a80000000844c000 a80000000844feb0
0000000000000000 ffffffff813919c0 000000001010ffe2 0000000000000000
...
Call Trace:
[<ffffffff8110a538>] handle_adel_int+0x28/0x30
[<ffffffff813919c0>] dst_rcu_free+0x50/0x68
[<ffffffff81365864>] dst_destroy+0x34/0x1a8
[<ffffffff813919c0>] dst_rcu_free+0x50/0x68
[<ffffffff8114a894>] __rcu_process_callbacks+0xac/0x2b8
[<ffffffff8113bcf8>] tasklet_action+0xa0/0xf8
[<ffffffff8113b8dc>] __do_softirq+0x124/0x168
[<ffffffff8113b990>] do_softirq+0x70/0x78
[<ffffffff8113be30>] ksoftirqd+0x88/0xe8
[<ffffffff8113bda8>] ksoftirqd+0x0/0xe8
[<ffffffff8114ddbc>] kthread+0x104/0x170
[<ffffffff8114dda4>] kthread+0xec/0x170
[<ffffffff8110be68>] kernel_thread_helper+0x10/0x18


Code: 00431024 1440ffaa 00000000 <89040000> 99040003 24020000 1440ffe7 7ca22403 08444786
Kernel panic - not syncing: Aiee, killing interrupt handler!