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. Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- 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
