Re: 2.2.0-pre9 ugliness on udb/alpha

Richard Henderson (rth@twiddle.net)
Sat, 23 Jan 1999 12:55:29 -0800


On Fri, Jan 22, 1999 at 10:04:30PM -0600, Kenneth Preslan wrote:
> I get a similar error installing the Qlogic FC SCSI module on the Alpha.
> I first saw this in pre8. It looks like Alpha threads are broken somehow.
>
> Ken
>
> My ksymoops:
>
> scsi_eh_1(387): Instruction fault 4
> pc = [<fffffc00004573dc>] ra = [<fffffc000040c704>] ps = 0000
> r0 = 0000000000000009 r1 = 0000000000000001 r2 = fffffc0007897df8
> r3 = fffffc00060cbd88 r4 = ffffffffffffffff r5 = 000000000000000a
> r6 = fffffc0000444009 r7 = fffffc00060c8342 r8 = fffffc00060c8000
> r16= fffffc00060cbd88 r17= 0000000000000001 r18= 0000000000000000
> r19= 000000000000000a r20= fffffffffffffffb r21= 0000000000000000
> r22= fffffc000044adc8 r23= fffffc000040d0c4 r24= fffffc00060cbd88
> r25= 000000000000000a r27= fffffc00004573d8 r28= fffffc000040f7d4
> gp = fffffc0000476d40 sp = fffffc00060cbcc8
> Code: 00000000 00000000 00457360 <fffffc00> 00000000 00000000 00000000 00000000 00000000
>
> >>EIP: fffffc00004573dc <fifo_inode_operations+4/a0>

Ok, this is clearly the end problem -- this isn't a function, it's data.
As to how we got there... Presuming we got there via a bsr or jsr, the
address is in ra = [<fffffc000040c704>].

> Trace: fffffc000040f7d4 <sprintf+1edc/327a8>
> Trace: fffffc000040d0c4 <simple_strtoul+384/548>
> Trace: fffffc00003f0050 <scsi_sleep+1640/2560>
> Trace: fffffc00003106e8 <__kernel_thread+50/68>
> Trace: fffffc00003effd8 <scsi_sleep+15c8/2560>

The tracelog is suspect -- simple_strtoul doesn't call anything,
though scsi_sleep does call sprintf indirectly. Further, sprintf
isn't 0x1edc bytes long, only 0x68.

I suppose it is possible that something is wrong with kernel_thread
wrt modules. An invalid gp would explain much of this wierdness.
But I remember fixing that up way earlier in the 2.1 series, and I
just went back over that call chain and didn't see anything amiss.

Can you point to any particular change from pre7 that causes the problem?

r~

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