From fd22aef8b47cfc068448df65c1183698b0abd815 Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Thu, 13 Apr 2017 12:17:37 +0200 Subject: [PATCH] rbd: move rbd_unregister_watch() call into rbd_dev_image_release() rbd_dev->disk tear down vs rbd_watch_cb() race shouldn't be a problem anymore thanks to EXISTS and REMOVING checks in rbd_dev_update_size(). A similar race could occur on "rbd map", see commit 811c66887746 ("rbd: fix rbd map vs notify races"). Signed-off-by: Ilya Dryomov Reviewed-by: Jason Dillaman --- drivers/block/rbd.c | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 0191a3c..b299ed0 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5964,6 +5964,8 @@ static int rbd_dev_header_name(struct rbd_device *rbd_dev) static void rbd_dev_image_release(struct rbd_device *rbd_dev) { rbd_dev_unprobe(rbd_dev); + if (rbd_dev->opts) + rbd_unregister_watch(rbd_dev); rbd_dev->image_format = 0; kfree(rbd_dev->spec->image_id); rbd_dev->spec->image_id = NULL; @@ -6126,15 +6128,8 @@ static ssize_t do_rbd_add(struct bus_type *bus, rbd_dev->mapping.read_only = read_only; rc = rbd_dev_device_setup(rbd_dev); - if (rc) { - /* - * rbd_unregister_watch() can't be moved into - * rbd_dev_image_release() without refactoring, see - * commit 1f3ef78861ac. - */ - rbd_unregister_watch(rbd_dev); + if (rc) goto err_out_image_probe; - } rc = count; out: @@ -6275,14 +6270,7 @@ static ssize_t do_rbd_remove(struct bus_type *bus, if (__rbd_is_lock_owner(rbd_dev)) rbd_unlock(rbd_dev); up_write(&rbd_dev->lock_rwsem); - rbd_unregister_watch(rbd_dev); - /* - * Don't free anything from rbd_dev->disk until after all - * notifies are completely processed. Otherwise - * rbd_bus_del_dev() will race with rbd_watch_cb(), resulting - * in a potential use after free of rbd_dev->disk or rbd_dev. - */ rbd_dev_device_release(rbd_dev); rbd_dev_image_release(rbd_dev); rbd_dev_destroy(rbd_dev); -- 2.7.4