> I am not sure what does assignment of pointers mean in this context. > ptr_ring is designed for a single producer and a single consumer. For > why it works see explanation about data dependencies in > Documentation/memory-barriers.txt. You will have to be more specific > about the data race that you see if you expect more specific answers.
Hi, ptr_ring_produce_any(sc->recv[chnl]->msgs, &item_recv_push[item_recv_push_index]) needs to have non-NULL pointer assigned for item_recv_push[item_recv_push_index] , right ? Note: ptr_ring_produce_any() occurs in interrupt handler, while ptr_ring_consume_any() occurs in thread. https://gist.github.com/promach/7716ee8addcaa33fda140d74d1ad94d6/cdc6599b8313e265bdfb073a65a124e1ba3303a2#file-riffa_driver_ptr_ring-c-L306-L320 // TX (PC receive) scatter gather buffer is read. if (vect & (1<<((5*i)+1))) { recv = 1; item_recv_push[item_recv_push_index].val1 = EVENT_SG_BUF_READ; item_recv_push[item_recv_push_index].val2 = 0; // Keep track so the thread can handle this. if (ptr_ring_produce_any(sc->recv[chnl]->msgs, &item_recv_push[item_recv_push_index])) { printk(KERN_ERR "riffa: fpga:%d chnl:%d, recv sg buf read msg queue full\n", sc->id, chnl); } DEBUG_MSG(KERN_INFO "riffa: fpga:%d chnl:%d, recv sg buf read\n", sc->id, chnl); item_recv_push_index++; } The kernel log points me to ptr_ring_consume_any(). So, this is definitely data race issue with my own ptr_ring interfacing code. besides, I am also getting a reference to zero-length ring for the kernel dmesg log. I am not sure how this is related to the data race though. The kernel log points to https://github.com/torvalds/linux/blame/master/include/linux/ptr_ring.h#L175 (click open git blame on this line) Regards, Phung
