On 2/11/22 12:43, Jason Gunthorpe wrote: > On Tue, Feb 08, 2022 at 03:16:42PM -0600, Bob Pearson wrote: >> Well behaved applications will free all memory allocated by multicast >> but programs which do not clean up properly can leave behind allocated >> memory when the rxe driver is unloaded. This patch walks the red-black >> tree holding multicast group elements and then walks the list of attached >> qp's freeing the mca's and finally the mcg's. > > How does this happen? the ib core ensures that all uobjects are > destroyed, so if something is still in the rb tree here it means that > an earlier uobject destruction leaked it > > Jason The mc_grp and mc_elem objects are not rdma-core uobjects. So their memory is allocated by the rxe driver. They get created by ib_attach_mcast and destroyed by ib_detach_mcast. If an application crashes without calling a matching ib_detach_mcast for each attachment the driver would have leaked the memory. This patch fixes that. Bob
