[mythtv-users] Oops on simultaneous recordings...

Poul Petersen petersp at mail.alleft.com
Wed May 26 21:08:02 EDT 2004


	I've been trouble-shooting an intermittent problem for quite some time now,
and I can't draw a definitive list of conditions. So, I'm sending this email
just to see if anyone else has ever seen anything like this.

	I've got a separate master backend machine with two capture cards.
Every now and then (maybe 1 out of three times?) when the box needs to
record two shows at the same time, the machine will Oops about 10 minutes into
the recordings. If I then hard boot the machine, the recordings will start back
up and complete fine. 

	If I reboot the machine every day, the problem will still
occur every now and then (so it's not a memory leak). I've been running this
box for almost 16 months and in the begining I ran lots of tests with three
capture cards, and I don't remember it ever crashing. I think the problems
may have appeared when I upgraded to 0.14, but I can't be sure. At the
time I also upgraded the disk and added a LCD - these variables have all
been removed (I built a separate frontend and installed the LCD there,
and I removed the second hard drive). I also added extra case fans
in case it was thermally related. I also ran memtestx86 for a full
weekend with no errors.

	 I've worked around the problem by changing the encoder scheduling
so that the frontend gets the second recording, thus ensuring that the master
backend never has to perform two simultaneous recordings (unless I try to
record three shows at the same time, but I haven't needed to do that recently).
Since I made this change, the machine has been stable (it has not oopsed in 
over a month whereas it used to oops about once a week). 

	Below I've attached the Oops I usually see and the machine
specs. Notice that I usually get two Oops's, one in mythbackend and
the other in kswapd, sometimes kjournald, etc.

Thanks for reading...

-poul

Specs:
RedHat 9 w/ kernel 2.4.25
ASUS A7V8X-X, AMD XP2200+, 256MB
Myth-0.14 built from source
mysql-4.0.13
(2) WinTV Radio using bttv/btaudio
alsa-0.9.4 snd-via82xx (on-board)
ext3 filesystem
1GB of swap

kernel:  <1>Unable to handle kernel paging request at virtual address 35333c47
kernel: c0135b7d
kernel: *pde = 00000000
kernel: Oops: 0002
kernel: CPU:    0
kernel: EIP:    0010:[<c0135b7d>]    Tainted: P 
kernel: EFLAGS: 00010046
kernel: eax: 35333c43   ebx: c1305dd4   ecx: c1cfe000   edx: cdaba000
kernel: esi: 00000018   edi: c1cfecc0   ebp: c1205010   esp: ceaf7dc0
kernel: ds: 0018   es: 0018   ss: 0018
kernel: Process mythbackend (pid: 3911, stackpage=ceaf7000)
kernel: Stack: 00000282 c1cfecc0 c1cfecc0 c013547e c1305dd4 c1cfecc0 c1cfecc0 c0140c27 
kernel:        c1305dd4 c1cfecc0 c0142fdd c1cfecc0 00000000 c1205010 c0270358 00002366 
kernel:        c01362a7 c1205010 000001d2 ceaf6000 00000c80 000001d2 0000000c 00000020 
kernel: Call Trace:    [<c013547e>] [<c0140c27>] [<c0142fdd>] [<c01362a7>] [<c01364dd>]
kernel:   [<c0136553>] [<c0137422>] [<c014182e>] [<c0137730>] [<c012efe5>] [<c012f0bb>]
kernel:   [<d0830500>] [<c012f783>] [<c012fb7a>] [<c012ffa0>] [<c013012d>] [<c012ffa0>]
kernel:   [<c01acc10>] [<c013e863>] [<c0108dbf>]
kernel: Code: 89 50 04 c7 01 00 00 00 00 8b 43 08 8d 53 08 89 48 04 89 01 


>>EIP; c0135b7d <kmem_find_general_cachep+69d/1ee0>   <=====

>>ebx; c1305dd4 <_end+fec1dc/104f3488>
>>ecx; c1cfe000 <_end+19e4408/104f3488>
>>edx; cdaba000 <_end+d7a0408/104f3488>
>>edi; c1cfecc0 <_end+19e50c8/104f3488>
>>ebp; c1205010 <_end+eeb418/104f3488>
>>esp; ceaf7dc0 <_end+e7de1c8/104f3488>

Trace; c013547e <kmem_cache_free+1e/30>
Trace; c0140c27 <bread+e7/100>
Trace; c0142fdd <try_to_free_buffers+5d/1f0>
Trace; c01362a7 <kmem_find_general_cachep+dc7/1ee0>
Trace; c01364dd <kmem_find_general_cachep+ffd/1ee0>
Trace; c0136553 <kmem_find_general_cachep+1073/1ee0>
Trace; c0137422 <_alloc_pages+62/200>
Trace; c014182e <block_read_full_page+1ee/2c0>
Trace; c0137730 <__alloc_pages+170/270>
Trace; c012efe5 <filemap_fdatawait+1c5/350>
Trace; c012f0bb <filemap_fdatawait+29b/350>
Trace; d0830500 <[ext3].text.start+4480/cb0d>
Trace; c012f783 <grab_cache_page_nowait+183/220>
Trace; c012fb7a <do_generic_file_read+32a/820>
Trace; c012ffa0 <do_generic_file_read+750/820>
Trace; c013012d <generic_file_read+bd/870>
Trace; c012ffa0 <do_generic_file_read+750/820>
Trace; c01acc10 <ide_dma_intr+0/430>
Trace; c013e863 <default_llseek+2a3/ce0>
Trace; c0108dbf <__up_wakeup+128f/1660>

Code;  c0135b7d <kmem_find_general_cachep+69d/1ee0>
00000000 <_EIP>:
Code;  c0135b7d <kmem_find_general_cachep+69d/1ee0>   <=====
   0:   89 50 04                  mov    %edx,0x4(%eax)   <=====
Code;  c0135b80 <kmem_find_general_cachep+6a0/1ee0>
   3:   c7 01 00 00 00 00         movl   $0x0,(%ecx)
Code;  c0135b86 <kmem_find_general_cachep+6a6/1ee0>
   9:   8b 43 08                  mov    0x8(%ebx),%eax
Code;  c0135b89 <kmem_find_general_cachep+6a9/1ee0>
   c:   8d 53 08                  lea    0x8(%ebx),%edx
Code;  c0135b8c <kmem_find_general_cachep+6ac/1ee0>
   f:   89 48 04                  mov    %ecx,0x4(%eax)
Code;  c0135b8f <kmem_find_general_cachep+6af/1ee0>
  12:   89 01                     mov    %eax,(%ecx)


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