On Wed, Apr 10, 2019 at 11:18:57AM -0300, Jason Gunthorpe wrote: > On Wed, Apr 10, 2019 at 02:13:03PM +0000, Parav Pandit wrote: > > > > Parav, > > > > > > Boot with rcu_dereference produces the following warning. > > > > > > [ 7.921247] mlx5_core 0000:00:0c.0: firmware version: 3.10.9999 > > > [ 7.921730] mlx5_core 0000:00:0c.0: 0.000 Gb/s available PCIe bandwidth > > > (Unknown speed x255 link) > > > [ 8.299897] mlx5_ib: Mellanox Connect-IB Infiniband driver v5.0-0 > > > [ 8.307859] > > > [ 8.307989] ============================= > > > [ 8.308084] WARNING: suspicious RCU usage > > > [ 8.308193] 5.1.0-rc2+ #278 Not tainted > > > [ 8.308302] ----------------------------- > > > [ 8.308446] drivers/infiniband/core/cache.c:302 suspicious > > > rcu_dereference_check() usage! > > > > > > > > > Yes. So lets do > > > > rcu_dereference_protected(attr->ndev, 1); > > > > with below updated comment? > > > > + /* rcu_dereference is not needed because GID attr being passed as input during > > + * GID addition cannot change. It is used only to avoid smatch complain. > > + */ > > Why cannot it change? > > You don't need to talk about smatch, the use of > rcu_dereference_protected is self-explanatory. While you are discussing the best comment, I tried it and it worked. Jason, do I need to resend v2? Thanks > > Jason
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