Instable kernel (2.6.29 or 2.6.31) on MPC8548 with 2 GByte RAM

[willy jacobs]

On our MPC8548 (latest die revision) based boards with 2 GByte DDR2 RAM we see an stable kernel when

CONFIG_HIGHMEM is not set

In this case only the first 768 MB will be used (as reported by /proc/cpuinfo).
Tested with/without the RT-patches for 2.6.29.6(-rt23) and 2.6.31.2(-rt13) kernels.

With CONFIG_HIGHMEM=y (2048 MB reported) we see (under "heavy" load conditions) regulary page
errors like this (with/without RT patches):

BUG: Bad page state in process loadgen  pfn:7e31d
page:c17c23a0 flags:80000000 count:0 mapcount:-128 mapping:(null) index:48105
Call Trace:
[ef867d20] [c00072ac] show_stack+0x34/0x160 (unreliable)
[ef867d50] [c006fcd0] bad_page+0x90/0x13c
[ef867d70] [c0070d94] get_page_from_freelist+0x424/0x45c
[ef867de0] [c0070ea4] __alloc_pages_nodemask+0xd8/0x48c
[ef867e40] [c0082bf0] handle_mm_fault+0x404/0x740
[ef867e90] [c00131bc] do_page_fault+0x150/0x460
[ef867f40] [c001017c] handle_page_fault+0xc/0x80

With the RT-patches we see already during Linux startup at lot of these errors (from several processes):

BUG: scheduling while atomic: pam_console_app/0x00000001/802, CPU#0
Modules linked in:
Call Trace:
[ef28dce0] [c00072ac] show_stack+0x34/0x160 (unreliable)
[ef28dd10] [c002fa90] __schedule_bug+0x6c/0x80
[ef28dd30] [c02660fc] __schedule+0x264/0x338
[ef28dd60] [c0266400] schedule+0x1c/0x40
[ef28dd70] [c0267898] rt_spin_lock_slowlock+0x124/0x264
[ef28dde0] [c0079154] __lru_cache_add+0x24/0xa8
[ef28de00] [c008ee04] page_add_new_anon_rmap+0x58/0x88
[ef28de20] [c0086ff8] handle_mm_fault+0x5a4/0x804
[ef28de80] [c0013590] do_page_fault+0x14c/0x49c
[ef28df40] [c00101c4] handle_page_fault+0xc/0x80
BUG: scheduling while atomic: pam_console_app/0x00000001/807, CPU#0
Modules linked in:
Call Trace:
[ef323a30] [c00072ac] show_stack+0x34/0x160 (unreliable)
[ef323a60] [c002fa90] __schedule_bug+0x6c/0x80
[ef323a80] [c02660fc] __schedule+0x264/0x338
[ef323ab0] [c0266400] schedule+0x1c/0x40
[ef323ac0] [c0267898] rt_spin_lock_slowlock+0x124/0x264
[ef323b30] [c0079154] __lru_cache_add+0x24/0xa8
[ef323b50] [c008ee04] page_add_new_anon_rmap+0x58/0x88
[ef323b70] [c0086ff8] handle_mm_fault+0x5a4/0x804
[ef323bd0] [c0013590] do_page_fault+0x14c/0x49c
[ef323c90] [c00101c4] handle_page_fault+0xc/0x80
[ef323d50] [00000007] 0x7
[ef323d80] [c0071320] generic_file_aio_read+0x2d4/0x6bc
[ef323e00] [c00ffe98] nfs_file_read+0x124/0x178
[ef323e30] [c009d56c] do_sync_read+0xc4/0x138
[ef323ef0] [c009e0a4] vfs_read+0xc4/0x188
[ef323f10] [c009e514] sys_read+0x4c/0x90
[ef323f40] [c000fd84] ret_from_syscall+0x0/0x3c

Anyone experience with MPC8548 with 2 GByte RAM (HIGHMEM)?

Regards,
-- 
willy
Unclassified


------------------------------------------------------------------------------------------------------------
Disclaimer:

If you are not the intended recipient of this email, please notify the sender and delete it. 
Any unauthorized copying, disclosure or distribution of this email or its attachment(s) is forbidden. 
Thales Nederland BV will not accept liability for any damage caused by this email or its attachment(s). 
Thales Nederland BV is seated in Hengelo and is registered at the Chamber of Commerce under number 06061578.
------------------------------------------------------------------------------------------------------------