Re: [uml-devel] [BUG: UML 2.6.11-rc4-bk-latest] sleeping function called from invalid context and segmentation fault

[Anton Altaparmakov <aia21@cam.ac.uk>]

On Wed, 2005-02-16 at 19:35 +0100, Blaisorblade wrote:
> On Monday 14 February 2005 12:48, Anton Altaparmakov wrote:
> > Hi,
> >
> > I get a few Debug messages of the form from UML:
> >
> > Debug: sleeping function called from invalid context at
> > include/asm/arch/semaphore.h:107
> > in_atomic():0, irqs_disabled():1
> > Call Trace:
> > 087d77b0:  [<0809aaa5>] __might_sleep+0x135/0x180
> > 087d77d8:  [<084d377f>] mcount+0xf/0x20
> > 087d77e0:  [<0807cc13>] uml_console_write+0x33/0x80
> 
> > Most are coming via uml_console_write.
> The problem is that the UML tty drivers use a semaphore instead of a spinlock 
> for the locking, which also causes some other problems.
> 
> The attached patch should fix this, but I've not yet made sure it is not 
> deadlock-prone (I didn't hit any during some very limited testing).
> 
> So it's not yet ready for 2.6.11.

Trying with the above patch in now only get two "sleeping function
called from invalid context" warnings during boot and none during
running.  However I get a lot of those errors:

arch/um/drivers/line.c:262: spin_lock(arch/um/drivers/line.c:085b5900)
already locked by arch/um/drivers/line.c/262

Also both before and after the patch I see a lot of messages like:

kernel: line_write_room: tty2: no room left in buffer

Best regards,

        Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/



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