Hey, On Thu, Sep 26, 2013 at 08:43:51AM +1000, Dave Chinner wrote: > On Wed, Sep 25, 2013 at 04:08:54PM +0800, majianpeng wrote: > > Hi, > > How about this patch? > > This bug can easily to reproduce. > > dd if=/dev/zero of=/dev/sdb bs=64k > > For a while, remove the disk. At my machine, it at most 100% occured. > > ... > > > > > >This bug introduced by commit ef3b101925f2170c. > > >I think the situation is like: > > >remove disk flush_thread_work > > >bdi_destroy() > > > bdi_unregister() > > > bdi->dev = NULL > > > bdi_writeback_workfn() > > You're just papering over the larger problem, in that the writeback > work is running concurrently with the bdi_unregister() function that > is tearing the bdi down. You should try to fix the underlying race > condition, as documented in bdi_destroy. Given that it's a fix for a reliably reproducible oops, I think papering over is better than nothing as long as it's clearly labeled as such. Jianpeng, can you please make it clear both in the description and patch that this is a bandaid for now and bdi shutdown sequence needs to be fixed properly later? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
