Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx> writes: > On Wed, 25 Feb 2015 16:11:27 +0100 > Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote: > >> On Wed, 25 Feb 2015 15:36:02 +0100 >> "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: >> >> > virtio balloon has this code: >> > wait_event_interruptible(vb->config_change, >> > (diff = towards_target(vb)) != 0 >> > || vb->need_stats_update >> > || kthread_should_stop() >> > || freezing(current)); >> > >> > Which is a problem because towards_target() call might block after >> > wait_event_interruptible sets task state to TAST_INTERRUPTIBLE, causing >> > the task_struct::state collision typical of nesting of sleeping >> > primitives >> > >> > See also http://lwn.net/Articles/628628/ or Thomas's >> > bug report >> > http://article.gmane.org/gmane.linux.kernel.virtualization/24846 >> > for a fuller explanation. >> > >> > To fix, rewrite using wait_woken. >> > >> > Cc: stable@xxxxxxxxxxxxxxx >> > Reported-by: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx> >> > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> >> > --- >> > >> > changes from v1: >> > remove wait_event_interruptible >> > noticed by Cornelia Huck <cornelia.huck@xxxxxxxxxx> >> > >> > drivers/virtio/virtio_balloon.c | 19 ++++++++++++++----- >> > 1 file changed, 14 insertions(+), 5 deletions(-) >> > >> >> I was able to reproduce Thomas' original problem and can confirm that >> it is gone with this patch. >> >> Reviewed-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx> > > Right, I just applied the patch on my system, too, and the problem is > indeed gone! Thanks for the quick fix! > > Tested-by: Thomas Huth <thuth@xxxxxxxxxxxxxxxxxx> Applied. Thanks, Rusty. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
