Hello, (cc'ing Jan) On Fri, Feb 26, 2016 at 02:19:20PM +0800, Peter Chen wrote: > On Thu, Feb 25, 2016 at 05:01:12PM -0500, Tejun Heo wrote: > > Hello, Peter. > > > > On Wed, Feb 24, 2016 at 03:24:30PM +0800, Peter Chen wrote: > > > > You might want to complain to the block-layer people about this. I > > > > don't know if anything can be done to fix it. > > > > > > > > Or maybe flush_work and flush_delayed_work can be changed to avoid > > > > blocking if the workqueue is frozen. Tejun? > > > > > > > > > > I have a patch to show the root cause of this issue. > > > > > > http://www.spinics.net/lists/linux-usb/msg136815.html > > > > I don't get it. Why would it deadlock? Shouldn't things get rolling > > once the workqueues are thawed? > > The workqueue writeback can't be thawed due to driver's resume > (dpm_complete) is lock nested, and can't be finished. Ugh... that's nasty. I wonder whether the right thing to do is making writeback workers non-freezable. IOs are supposed to be blocked from lower layer anyway. Jan, what do you think? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
