Re: kernel access of bad area, sig: 11 ( mpc852t)

quoted

Hi,
Im having problem porting linux kernel 2.4.21 to our mpc852T custom
board.The kernel
panics randomly with sig 11.
The board boots up fine and we also get to the prompt.When we open 3-4
telnet sessions
and try to run some command the kernel panics.This is completely
random.Sometimes it
even panics before opening the telnet session.

One of the oops dump is:

------------------------------------------------------------------------=

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\

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Oops: kernel access of bad area, sig: 11
NIP: C0019FD0 XER: 00000000 LR: C001A06C SP: C1C33AD0 REGS: c1c33a20
TRAP: 0300    Not tainted
MSR: 00009032 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 11
DAR: 725F6578, DSISR: 0000000B
TASK =3D c1c32000[48] 'insmod' Last syscall: 5
last math 00000000 last altivec 00000000
GPR00: 7361726D C1C33AD0 C1C32000 00000000 C0113678 C0150000 C0150000
C014B210
GPR08: C014B210 C012D060 00000000 725F6578 04000024 00000000 00000000
00000000
GPR16: 00000000 00000000 00000000 00000000 00001032 01C33BA0 00000000
C0000000
GPR24: C014BE38 C0150000 C0110000 C0110000 C0140000 00000001 00000000
00000001
Call backtrace:
C001A0C8 C0016174 C0015FEC C0015CC0 C0005E38 C0004668 C1C33D10
C0004670 C004A380 C003FFD4 C00404D8 C0040AD4 C0040FF8 C00330D8
C00334AC C000443C 1006EF48 1001FCF0 1002023C 10003A18 100036A0
300591AC 00000000
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quoted

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The call trace back is of not much help because it is different on all
oops.
We are using u-boot 1-1-3.

Thanks in advance.

You almost certainly have SDRAM problems.  If you have thoroughly checked
out the
complete address range statically, remember that burst accesses will not
occur until the
cache is turned on, so your problem may be with bursting.  But you can als=

o

have severe
problems like a missing address line and linux still run for a few seconds=

.

Mark Chambers

We've checked the SDRAM. The timings (UPM) look fine. The problem
however is that linux does not hang until after a few processes are
started.
If we boot to linux and leave it as it is, everything is fine and the
board remains working. However each time a few processes (4-5 telnet
sessions for eg.) are started the system either panics or hangs (goes
dead).

Thanks in advance,
Akshay