Re: 'bad: scheduling while atomic!', preempt kernel, 2.6.1-test11,reading an apparently duff DVD-R

[Linus Torvalds]

On Mon, 15 Dec 2003, Toad wrote:
>
> I got the following when trying to mount a particular DVD-R on Linux
> 2.6.0-test11, using an IDE DVD-RW drive, using SCSI emulation, with the
> preempt kernel option enabled, and taskfile I/O:
> (the middle bit was repeated several times):

ide-scsi does

        spin_lock_irqsave(&ide_lock, flags);
        while (HWGROUP(drive)->handler) {
                HWGROUP(drive)->handler = NULL;
                schedule_timeout(1);
        }

which is obvious crap. Scheduling while holding a spinlock is not a good
idea.

You could try dropping the lock over the schedule and re-aquire it
afterwards, but the comment tries to say that it is required for avoiding
new requests.

This is why ide-scsi needs a maintainer, btw - somebody who cares about
it, and actually tries to resolve the current mess.

		Linus
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