Re: Linux 3.19-rc5

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Wednesday, January 21, 2015 05:54:00 PM Peter Hurley wrote:
> On 01/21/2015 05:12 PM, Davidlohr Bueso wrote:
> > On Wed, 2015-01-21 at 22:37 +0100, Bruno Prémont wrote:
> >> On Wed, 21 January 2015 Bruno Prémont wrote:
> >>> On Tue, 20 January 2015 Linus Torvalds wrote:
> >>>> On Tue, Jan 20, 2015 at 6:02 AM, Bruno Prémont wrote:
> >>>>>
> >>>>> No idea yet which rc is the offender (nor exact patch), but on my not
> >>>>> so recent UP laptop with a pccard slot I have 2 pccardd kernel threads
> >>>>> converting my laptop into a heater.
> 
> [...]
> 
> >> Bisecting to the end did point me at (the warning traces produced in great
> >> quantities might not be the very same issue as the abusive CPU usage, but
> >> certainly look very related):
> >>   [CCing people on CC for the patch]
> >>
> >> commit 8eb23b9f35aae413140d3fda766a98092c21e9b0
> >> Author: Peter Zijlstra <peterz@infradead.org>
> >> Date:   Wed Sep 24 10:18:55 2014 +0200
> 
> [...]
> 
> >> Which does produce the following trace (hand-copied most important parts of it):
> >>   Warning: CPU 0 PID: 68 at kernel/sched/core.c:7311 __might_sleep+0x143/0x170
> >>   do not call blocking ops when !TASK_RUNNING; state=1 set at [<c1436390>] pccardd+0xa0/0x3e0
> >>   ...
> >>   Call trace:
> >>     ...
> >>     __might_sleep+0x143/0x170
> >>     ? pccardd+0xa0/0x3e0
> >>     ? pccardd+0xa0/0x3e0
> >>     mutex_lock+0x17/0x2a
> >>     pccardd+0xe9/0x3e0
> >>     ? pcmcia_socket_uevent+0x30/0x30
> >>
> >> pccardd() is located in drivers/pcmcia/cs.c and seems to be of the structure
> >> Peter's patch wants to warn about.
> > 
> > Yeah setting current to interruptable so early in the game is bogus. It
> > should be set after unlocking the skt_mutex.
> 
> Yeah, but the debug check is triggering worse behavior, requiring
> bisecting back to the debug commit.

Yes, it is.

So I'm wondering is anyone is working on fixing this in any way?

It kind of sucks when this is happening on an otherwise perfectly usable
old(ish) machine ...

Rafael