Re: [BUG] kernel 2.6.15.4: soft lockup detected on CPU#0!

From: Bartlomiej Zolnierkiewicz
Date: Thu Feb 16 2006 - 08:31:18 EST


On 2/16/06, Andrew Morton <akpm@xxxxxxxx> wrote:
> Charles-Edouard Ruault <ce@xxxxxxxxxx> wrote:
> >
> > i was trying to rip a CD when the whole machine started to freeze
> > periodicaly, i then looked at the logs and found the following :
> >
> > Feb 12 19:23:39 ruault kernel: hdc: irq timeout: status=0x80 { Busy }
> > Feb 12 19:23:39 ruault kernel: ide: failed opcode was: unknown
> > Feb 12 19:23:39 ruault kernel: hdd: status timeout: status=0x80 { Busy }
> > Feb 12 19:23:39 ruault kernel: ide: failed opcode was: unknown
> > Feb 12 19:23:39 ruault kernel: hdd: drive not ready for command
>
> No idea what caused that.
>
> > Feb 12 19:23:39 ruault kernel: BUG: soft lockup detected on CPU#0!
>
> The following was merged today. Hopefully it suppresses this false
> positive.

Unfortunately it won't. Charles' problem is different (and the BUG
output is different!) - soft lockup got triggered for PIO handling in
ide-cd driver. This patch fixes the problem only for generic ATA PIO
routines (disks and [P]IDENTIFY), ATAPI PIO still needs fixing
(ide-cd/floppy/tape/scsi drivers).

Andrew, there is no "high level" function for ATAPI PIO as
ide_pio_datablock() for ATA PIO so fixing soft lockup false positives
would require going through all drivers and adding bunch of
touch_softlockup_watchdog() or using sledge-hammer approach
and touching watchdog in ide-iops.c:atapi_[input,output]_bytes().

BTW Charles' OOPS is for tainted (P) kernel (fglrx loaded)

Bartlomiej
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