Since nldev_deldev() (introduced by commit 060c642b2ab8 ("RDMA/nldev: Add support to add/delete a sub IB device through netlink") grabs a reference using ib_device_get_by_index() before calling ib_del_sub_device_and_put(), we need to drop that reference before returning -EOPNOTSUPP error. Reported-by: syzbot+881d65229ca4f9ae8c84@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84 Fixes: bca51197620a ("RDMA/core: Support IB sub device with type "SMI"") Signed-off-by: Tetsuo Handa --- The reproducer syzbot finally found was not for what I was investigating, but this is a bug which I can reproduce and test using the reproducer. drivers/infiniband/core/device.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 13e8a1714bbd..1174ab7da629 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -2881,8 +2881,10 @@ int ib_del_sub_device_and_put(struct ib_device *sub) { struct ib_device *parent = sub->parent; - if (!parent) + if (!parent) { + ib_device_put(sub); return -EOPNOTSUPP; + } mutex_lock(&parent->subdev_lock); list_del(&sub->subdev_list); -- 2.47.3