On Fri, Apr 21, 2017 at 03:16:28PM -0700, Omar Sandoval wrote: > On Tue, Apr 18, 2017 at 04:29:44PM -0700, Bart Van Assche wrote: > > One of the debugfs attributes allows to run a queue. Since running > > a queue after a queue has entered the "dead" state is not allowed > > and even can cause a kernel crash, unregister the debugfs attributes > > before a queue reaches the "dead" state. > > > > Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> > > Cc: Omar Sandoval <osandov@xxxxxx> > > Cc: Hannes Reinecke <hare@xxxxxxxx> > > --- > > block/blk-mq-sysfs.c | 31 ++++++------------------------- > > block/blk-sysfs.c | 3 +-- > > 2 files changed, 7 insertions(+), 27 deletions(-) > > > > diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c > > index 727e3b675130..1b2107f229ee 100644 > > --- a/block/blk-mq-sysfs.c > > +++ b/block/blk-mq-sysfs.c > > @@ -258,7 +258,7 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q) > > queue_for_each_hw_ctx(q, hctx, i) > > blk_mq_unregister_hctx(hctx); > > > > - blk_mq_debugfs_unregister_hctxs(q); > > + blk_mq_debugfs_unregister(q); > > This isn't what we want to do. First of all, we can't get remove the > /sys/kernel/debug/block/$dev directory until after we shutdown blktrace. > You unregister the top-level directory in other places, too. That should > only be done in the blk_release_queue() like it was originally. > > More importantly, this doesn't actually fix the issue at hand. The > blk_mq_debugfs_unregister_hctxs() call needs to be moved earlier. > Actually, can you please rename blk_mq_debugfs_unregister_mq() to make I meant can you please rename blk_mq_debugfs_unregister_hctxs() to blk_mq_debugfs_unregister_mq().
