RE: dying hdd causing MCE and panic (libata)

[Peer Chen]

It's unresolved machine check error and don't switch to register mode
and read the task file in the driver is the only way to avoid this
error.

BRs
Peer Chen
 

> -----Original Message-----
> From: Robert Hancock [mailto:hancockr@xxxxxxx] 
> Sent: Monday, April 21, 2008 2:21 AM
> To: Rumi Szabolcs
> Cc: linux-kernel@xxxxxxxxxxxxxxx; Peer Chen; Kuan Luo; Allen Martin
> Subject: Re: dying hdd causing MCE and panic (libata)
> 
> Rumi Szabolcs wrote:
> > Hello all!
> > 
> > A SATA drive in one of my servers has made some final steps towards 
> > the grave and it has put out some obvious signs of this onto the 
> > console (ATA transactions failing) but then it has also 
> thrown an MCE 
> > (CPU context corrupt) and then the kernel has panicked.
> > This server is rock stable otherwise and used to make 
> uptimes measured 
> > in months between planned restarts.
> > 
> > The machine has been removed from power completely and restarted 
> > multiple times but during the boot process it always 
> crashed with an 
> > MCE or a panic or both.
> > 
> > Sorry but I cannot provide exact debug information right 
> now because I 
> > wasn't physically there at the time and I'm still 250kms away from 
> > that server. In fact I've remotely guided two people without a clue 
> > through the phone and they have read things from the 
> console for me, 
> > restarted the machine, etc.
> > 
> > So in the end I told them to open up the server and pull the SATA 
> > cable from that particular drive. Suddenly all the MCEs and 
> panics had 
> > gone away and the machine is running fine since then.
> > 
> > Hardware:
> > 
> > - Nforce4 based motherboard (chipset integrated SATA ports)
> > - Athlon64 single core CPU
> > - Diamondmax 9 SATA hard drive
> > 
> > Kernel:
> > 
> > 2.6.23-gentoo-r3 (no preempt, no smp)
> > 
> > My questions:
> > 
> > - Is it normal that a simple hard disk failure (that is not 
> even the 
> > system disk) causes MCEs and kernel panics?
> > 
> > - Is this a problem that is induced completely on the 
> hardware level 
> > (eg. the southbridge going crazy and making the whole hardware 
> > platform unstable) or a problem that could be fixed or handled 
> > properly on the software (kernel) level?
> 
> It's known that nForce4 ADMA can in certain cases hang on 
> error handling and cause an MCE when we attempt to switch the 
> controller into register mode and read the  ATA registers in 
> order to diagnose the problem. The MCE indicates the CPU 
> timed out waiting for a register read from the chipset on the 
> HyperTranport bus. It's not presently known why this is, or 
> what we could do differently to avoid this problem. We're 
> presently hampered by lack of public information from NVIDIA 
> on this controller to fix this, so the ball is kind of in 
> NVIDIA's court.
> 
> In the latest kernels sata_nv ADMA support is being disabled 
> by default, which may prevent this from happening. However, 
> some odd hotplug/error handling behavior was seen on these 
> controllers before ADMA support was implemented, so it may 
> not entirely fix the problem.
> 
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