If the rbd_dev_create() fails after assignment 'opts' to 'rbd_dev->opts',
double free of 'rbd_options' happens:
one is in rbd_dev_free() and another one is in do_rbd_add().
If the rbd_dev_create() fails, for 'spec' it will be freed in
rbd_dev_create()->rbd_spec_put() first and then in do_rbd_add()
it will call rbd_spec_put() again. The same for 'rbd_client'.
Unlike 'rbd_dev->opts', 'rbd_dev->spec' and 'rbd_dev->rbd_client'
are ref-counted, that's why the ref-count underflow warning
should be generated in rbd_spec_put() and rbd_put_client()
to handle the return values of kref_put().
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 1643dfa4c2c8 ("rbd: introduce a per-device ordered workqueue")
Signed-off-by: Natalia Petrova <n.petrova@xxxxxxxxxx>
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
---
v2: Remarks on the processing of 'rbd_dev->spec' and 'rbd_dev->rbd_client'
by Ilya Dryomov <idryomov@xxxxxxxxx> and Xiubo Li <xiubli@xxxxxxxxxx>
were taken into account.
drivers/block/rbd.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 04453f4a319c..f3f253febe0f 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -889,8 +889,10 @@ static void rbd_client_release(struct kref *kref)
*/
static void rbd_put_client(struct rbd_client *rbdc)
{
- if (rbdc)
- kref_put(&rbdc->kref, rbd_client_release);
+ if (rbdc) {
+ if (!kref_put(&rbdc->kref, rbd_client_release))
+ pr_warn("The reference count underflow\n");
+ }
}
/*
@@ -5225,8 +5227,10 @@ static struct rbd_spec *rbd_spec_get(struct rbd_spec *spec)
static void rbd_spec_free(struct kref *kref);
static void rbd_spec_put(struct rbd_spec *spec)
{
- if (spec)
- kref_put(&spec->kref, rbd_spec_free);
+ if (spec) {
+ if (!kref_put(&spec->kref, rbd_spec_free))
+ pr_warn("The reference count underflow\n");
+ }
}
static struct rbd_spec *rbd_spec_alloc(void)
@@ -5357,7 +5361,6 @@ static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
if (!rbd_dev)
return NULL;
- rbd_dev->opts = opts;
/* get an id and fill in device name */
rbd_dev->dev_id = ida_simple_get(&rbd_dev_id_ida, 0,
@@ -5372,6 +5375,7 @@ static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
if (!rbd_dev->task_wq)
goto fail_dev_id;
+ rbd_dev->opts = opts;
/* we have a ref from do_rbd_add() */
__module_get(THIS_MODULE);
--
2.34.1
