| Message ID | 20200227203651.GA27185@ziepe.ca (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 32ac9e4399b12d3e54d312a0e0e30ed5cd19bd4e |
| Delegated to: | Jason Gunthorpe |
| Headers | show |
| Series | RDMA/cma: Teach lockdep about the order of rtnl and lock | expand |
On Thu, Feb 27, 2020 at 04:36:51PM -0400, Jason Gunthorpe wrote: > This lock ordering only happens when bonding is enabled and > a certain bonding related event fires. However, since it can happen this > is a global restriction on lock ordering. > > Teach lockdep about the order directly and unconditionally so bugs here > are found quickly. > > See https://syzkaller.appspot.com/bug?extid=55de90ab5f44172b0c90 > > Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> > --- > drivers/infiniband/core/cma.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) Lets give it a go, applied to for-next Jason
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index 5165158a7aaa7d..c623d54ac9f944 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -4789,6 +4789,19 @@ static int __init cma_init(void) { int ret; + /* + * There is a rare lock ordering dependency in cma_netdev_callback() + * that only happens when bonding is enabled. Teach lockdep that rtnl + * must never be nested under lock so it can find these without having + * to test with bonding. + */ + if (IS_ENABLED(CONFIG_LOCKDEP)) { + rtnl_lock(); + mutex_lock(&lock); + mutex_unlock(&lock); + rtnl_unlock(); + } + cma_wq = alloc_ordered_workqueue("rdma_cm", WQ_MEM_RECLAIM); if (!cma_wq) return -ENOMEM;
This lock ordering only happens when bonding is enabled and a certain bonding related event fires. However, since it can happen this is a global restriction on lock ordering. Teach lockdep about the order directly and unconditionally so bugs here are found quickly. See https://syzkaller.appspot.com/bug?extid=55de90ab5f44172b0c90 Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> --- drivers/infiniband/core/cma.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) This will trigger siw to fail on module load, maybe other drivers too.