Re: 2.6.2-rc1-mm2: sleep_on_timeout with parport

From: viro
Date: Sun Jan 25 2004 - 12:58:18 EST


On Sun, Jan 25, 2004 at 04:55:01PM +0100, Jan Ischebeck wrote:
> Trying to print without switching the printer on I got the following
> error messages.
>
> lp0 out of paper
> Badness in interruptible_sleep_on_timeout at kernel/sched.c:2245
> Call Trace:
> [<c0121a6f>] interruptible_sleep_on_timeout+0x10f/0x120
> [<c0121500>] default_wake_function+0x0/0x20
> [<e0a34e5f>] parport_release+0x7f/0x140 [parport]

Yeah... parport locking primitives (and, frankly, the rest of parport
API) apparently had been designed on serious drugs.

I'm cleaning up that crap; some patches are already in -mm, more will
follow. In particular, yes, parprt_claim()/parport_claim_or_block()/
parport_release() is racy and most of the users have problems with
missing wakeups.
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