diff options
author | Jason Gunthorpe <jgg@nvidia.com> | 2020-06-26 14:49:10 -0300 |
---|---|---|
committer | Jason Gunthorpe <jgg@nvidia.com> | 2020-07-02 14:25:42 -0300 |
commit | 0cb42c0265837fafa2b4f302c8a7fed2631d7869 (patch) | |
tree | a7d90144f48831f74e09ef81f2972d1b38f16f48 /drivers/infiniband/core | |
parent | 65936bf25f90fe440bb2d11624c7d10fab266639 (diff) |
RDMA/core: Fix bogus WARN_ON during ib_unregister_device_queued()
ib_unregister_device_queued() can only be used by drivers using the new
dealloc_device callback flow, and it has a safety WARN_ON to ensure
drivers are using it properly.
However, if unregister and register are raced there is a special
destruction path that maintains the uniform error handling semantic of
'caller does ib_dealloc_device() on failure'. This requires disabling the
dealloc_device callback which triggers the WARN_ON.
Instead of using NULL to disable the callback use a special function
pointer so the WARN_ON does not trigger.
Fixes: d0899892edd0 ("RDMA/device: Provide APIs from the core code to help unregistration")
Link: https://lore.kernel.org/r/0-v1-a36d512e0a99+762-syz_dealloc_driver_jgg@nvidia.com
Reported-by: syzbot+4088ed905e4ae2b0e13b@syzkaller.appspotmail.com
Suggested-by: Hillf Danton <hdanton@sina.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/infiniband/core')
-rw-r--r-- | drivers/infiniband/core/device.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index 1335ed1f1e4a..40cf07129f66 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -1339,6 +1339,10 @@ out: return ret; } +static void prevent_dealloc_device(struct ib_device *ib_dev) +{ +} + /** * ib_register_device - Register an IB device with IB core * @device: Device to register @@ -1409,11 +1413,11 @@ int ib_register_device(struct ib_device *device, const char *name) * possibility for a parallel unregistration along with this * error flow. Since we have a refcount here we know any * parallel flow is stopped in disable_device and will see the - * NULL pointers, causing the responsibility to + * special dealloc_driver pointer, causing the responsibility to * ib_dealloc_device() to revert back to this thread. */ dealloc_fn = device->ops.dealloc_driver; - device->ops.dealloc_driver = NULL; + device->ops.dealloc_driver = prevent_dealloc_device; ib_device_put(device); __ib_unregister_device(device); device->ops.dealloc_driver = dealloc_fn; @@ -1462,7 +1466,8 @@ static void __ib_unregister_device(struct ib_device *ib_dev) * Drivers using the new flow may not call ib_dealloc_device except * in error unwind prior to registration success. */ - if (ib_dev->ops.dealloc_driver) { + if (ib_dev->ops.dealloc_driver && + ib_dev->ops.dealloc_driver != prevent_dealloc_device) { WARN_ON(kref_read(&ib_dev->dev.kobj.kref) <= 1); ib_dealloc_device(ib_dev); } |