diff options
| author | Daniel Wagner <dwagner@suse.de> | 2021-09-02 12:20:02 +0300 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2021-09-13 18:04:04 +0300 |
| commit | 9edceaf43050f5ba1dd7d0011bcf68a736a17743 (patch) | |
| tree | a6e87f932394ccbc624e92414f4306d543f76af9 /drivers/nvme | |
| parent | 0bd46e22c5ec3dbfb81b60de475151e3f6b411c2 (diff) | |
| download | linux-9edceaf43050f5ba1dd7d0011bcf68a736a17743.tar.xz | |
nvme: avoid race in shutdown namespace removal
When we remove the siblings entry, we update ns->head->list, hence we
can't separate the removal and test for being empty. They have to be
in the same critical section to avoid a race.
To avoid breaking the refcounting imbalance again, add a list empty
check to nvme_find_ns_head.
Fixes: 5396fdac56d8 ("nvme: fix refcounting imbalance when all paths are down")
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/nvme')
| -rw-r--r-- | drivers/nvme/host/core.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 7efb31b87f37..97f8211cf92c 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3524,7 +3524,9 @@ static struct nvme_ns_head *nvme_find_ns_head(struct nvme_subsystem *subsys, lockdep_assert_held(&subsys->lock); list_for_each_entry(h, &subsys->nsheads, entry) { - if (h->ns_id == nsid && nvme_tryget_ns_head(h)) + if (h->ns_id != nsid) + continue; + if (!list_empty(&h->list) && nvme_tryget_ns_head(h)) return h; } @@ -3843,6 +3845,10 @@ static void nvme_ns_remove(struct nvme_ns *ns) mutex_lock(&ns->ctrl->subsys->lock); list_del_rcu(&ns->siblings); + if (list_empty(&ns->head->list)) { + list_del_init(&ns->head->entry); + last_path = true; + } mutex_unlock(&ns->ctrl->subsys->lock); /* guarantee not available in head->list */ @@ -3863,13 +3869,6 @@ static void nvme_ns_remove(struct nvme_ns *ns) list_del_init(&ns->list); up_write(&ns->ctrl->namespaces_rwsem); - /* Synchronize with nvme_init_ns_head() */ - mutex_lock(&ns->head->subsys->lock); - if (list_empty(&ns->head->list)) { - list_del_init(&ns->head->entry); - last_path = true; - } - mutex_unlock(&ns->head->subsys->lock); if (last_path) nvme_mpath_shutdown_disk(ns->head); nvme_put_ns(ns); |