[linux-dvb] Crashes with kernel 2.4.30

[Bernard Hatt]

Having now experimented with this, I found that I have exactly
the same problem with 2.4.31, even running dvbdate from the
command line would crash the box.

The eventual fix was to take CONFIG_DEBUG_KERNEL out of
my .config (it was left in there from when I was playing
with the file-system API).

The CONFIG_DEBUG_KERNEL option appears to scribble over
free'd memory with 0x5a5a5a5a to detect uninitialised data,
and the crashes I was seeing was from where the kernel
tried to use this as a pointer:

Unable to handle kernel paging request at virtual address 5a5a5a5a
*pde = 00000000
CPU:    0
EIP:    0010:[<c011616c>]  Not tainted
Using defaults from ksymoops -t elf32-i386 -a i386
EFLAGS: 00010086
eax: f795bdb8   ebx: 5a5a5a5a     ecx: 00000001       edx: 00000003
esi: f795bdac   edi: f795bdb8     ebp: c03bfef8       esp: c03bfee0
ds: 0018        es: 0018       ss: 0018
Process swapper (pid: 0, stackpage=c03bf000)
Stack: 00000001 00000286 00000003 f78f9340 f795bdac f78f9380 f78f9248 f8960a1f
        f792b000 f7847dec f73a618c f7847dec f78f9580 00000000 00000000 03ffd403
        f7872300 00000000 f792b000 00000006 f8966014 f8961d75 f792b000 00000001
Call Trace:   [<f8960a1f>] [<f8961d75>] [<c01089a5>] [<c0108b54>] [<c01052e0]
  [<c010afd8>] [<c01052e0>] [<c0105303>] [<c0105372>] [<c0105000>]
Code: 8b 13 0f 0f 02 39 c3 74 3c 8b 4b fc 8b 01 85 45 f0 74 25 31

I don't know if the problem is in the dvb drivers or in
something else that it depends on (eg. usb), but I would be curious
to know if anyone else gets the same problem if they turn on
CONFIG_DEBUG_KERNEL.

Regards,

Bernard

Bernard Hatt wrote:
> I've been running 2.4.27 with linuxtv-dvb-1.1.1 and
> linuxtv-dvb-apps-1.1.0 for some time with no problems whatsoever.
> 
> Having now upgraded to 2.4.30 (re-compiling the linux-dvb modules)
> using dvb seems to cause the machine to lock up (completly frozen
> with just the caps lock and scroll lock flashing on the keyboard).
> 
> xine will start up and display the first channel, but will lock the
> machine if I change channel, and dvbdate will also cause this.
> 
> The hardware is a DEC-2000:
> P:  Vendor=0b48 ProdID=1006 Rev= 1.00
> S:  Manufacturer=TechnoTrend AG
> S:  Product=TechnoTrend DVB-S/-C/-T STB - USB Adapter
> I:  If#= 0 Alt= 0 #EPs= 8 Cls=00(>ifc ) Sub=00 Prot=00 Driver=ttusb-dec
> 
> Everything is stable again once I reboot with 2.4.27 ...
> 
> Have I missed something obvious in upgrading the kernel ?, is
> anyone else running with 2.4.30 ?
> 
> Thanks,
> 
> Bernard
> 
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