Hi Bobby, kernel test robot noticed the following build warnings:
url: https://github.com/intel-lab-lkp/linux/commits/Bobby-Eshleman/net-devmem-rename-tx_vec-to-vec-in-dmabuf-binding/20251105-092703 base: 255d75ef029f33f75fcf5015052b7302486f7ad2 patch link: https://lore.kernel.org/r/20251104-scratch-bobbyeshleman-devmem-tcp-token-upstream-v6-3-ea98cf4d40b3%40meta.com patch subject: [PATCH net-next v6 3/6] net: devmem: prepare for autorelease rx token management config: nios2-randconfig-r071-20251105 (https://download.01.org/0day-ci/archive/20251106/[email protected]/config) compiler: nios2-linux-gcc (GCC) 8.5.0 If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Reported-by: Dan Carpenter <[email protected]> | Closes: https://lore.kernel.org/r/[email protected]/ New smatch warnings: net/ipv4/tcp.c:2626 tcp_recvmsg_dmabuf() error: uninitialized symbol 'refs'. vim +/refs +2626 net/ipv4/tcp.c 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2485 static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2486 unsigned int offset, struct msghdr *msg, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2487 int remaining_len) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2488 { 45aa39492cf4dd Bobby Eshleman 2025-11-04 2489 struct net_devmem_dmabuf_binding *binding = NULL; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2490 struct dmabuf_cmsg dmabuf_cmsg = { 0 }; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2491 struct tcp_xa_pool tcp_xa_pool; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2492 unsigned int start; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2493 int i, copy, n; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2494 int sent = 0; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2495 int err = 0; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2496 int refs; refs needs to be initialized to zero. Best practice is to use CONFIG_INIT_STACK_ALL_PATTERN for testing. 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2497 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2498 tcp_xa_pool.max = 0; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2499 tcp_xa_pool.idx = 0; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2500 do { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2501 start = skb_headlen(skb); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2502 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2503 if (skb_frags_readable(skb)) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2504 err = -ENODEV; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2505 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2506 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2507 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2508 /* Copy header. */ 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2509 copy = start - offset; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2510 if (copy > 0) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2511 copy = min(copy, remaining_len); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2512 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2513 n = copy_to_iter(skb->data + offset, copy, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2514 &msg->msg_iter); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2515 if (n != copy) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2516 err = -EFAULT; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2517 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2518 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2519 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2520 offset += copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2521 remaining_len -= copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2522 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2523 /* First a dmabuf_cmsg for # bytes copied to user 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2524 * buffer. 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2525 */ 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2526 memset(&dmabuf_cmsg, 0, sizeof(dmabuf_cmsg)); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2527 dmabuf_cmsg.frag_size = copy; 18912c520674ec Stanislav Fomichev 2025-02-24 2528 err = put_cmsg_notrunc(msg, SOL_SOCKET, 18912c520674ec Stanislav Fomichev 2025-02-24 2529 SO_DEVMEM_LINEAR, 18912c520674ec Stanislav Fomichev 2025-02-24 2530 sizeof(dmabuf_cmsg), 18912c520674ec Stanislav Fomichev 2025-02-24 2531 &dmabuf_cmsg); 18912c520674ec Stanislav Fomichev 2025-02-24 2532 if (err) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2533 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2534 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2535 sent += copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2536 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2537 if (remaining_len == 0) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2538 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2539 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2540 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2541 /* after that, send information of dmabuf pages through a 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2542 * sequence of cmsg 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2543 */ 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2544 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2545 skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2546 struct net_iov *niov; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2547 u64 frag_offset; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2548 u32 token; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2549 int end; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2550 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2551 /* !skb_frags_readable() should indicate that ALL the 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2552 * frags in this skb are dmabuf net_iovs. We're checking 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2553 * for that flag above, but also check individual frags 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2554 * here. If the tcp stack is not setting 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2555 * skb_frags_readable() correctly, we still don't want 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2556 * to crash here. 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2557 */ 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2558 if (!skb_frag_net_iov(frag)) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2559 net_err_ratelimited("Found non-dmabuf skb with net_iov"); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2560 err = -ENODEV; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2561 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2562 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2563 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2564 niov = skb_frag_net_iov(frag); 69e39537b66232 Pavel Begunkov 2025-02-04 2565 if (!net_is_devmem_iov(niov)) { 69e39537b66232 Pavel Begunkov 2025-02-04 2566 err = -ENODEV; 69e39537b66232 Pavel Begunkov 2025-02-04 2567 goto out; 69e39537b66232 Pavel Begunkov 2025-02-04 2568 } 69e39537b66232 Pavel Begunkov 2025-02-04 2569 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2570 end = start + skb_frag_size(frag); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2571 copy = end - offset; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2572 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2573 if (copy > 0) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2574 copy = min(copy, remaining_len); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2575 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2576 frag_offset = net_iov_virtual_addr(niov) + 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2577 skb_frag_off(frag) + offset - 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2578 start; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2579 dmabuf_cmsg.frag_offset = frag_offset; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2580 dmabuf_cmsg.frag_size = copy; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2581 45aa39492cf4dd Bobby Eshleman 2025-11-04 2582 binding = net_devmem_iov_binding(niov); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2583 45aa39492cf4dd Bobby Eshleman 2025-11-04 2584 if (!sk->sk_devmem_info.binding) 45aa39492cf4dd Bobby Eshleman 2025-11-04 2585 sk->sk_devmem_info.binding = binding; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2586 45aa39492cf4dd Bobby Eshleman 2025-11-04 2587 if (sk->sk_devmem_info.binding != binding) { 45aa39492cf4dd Bobby Eshleman 2025-11-04 2588 err = -EFAULT; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2589 goto out; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2590 } 45aa39492cf4dd Bobby Eshleman 2025-11-04 2591 45aa39492cf4dd Bobby Eshleman 2025-11-04 2592 if (sk->sk_devmem_info.autorelease) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2593 err = tcp_xa_pool_refill(sk, &tcp_xa_pool, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2594 skb_shinfo(skb)->nr_frags - i); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2595 if (err) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2596 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2597 45aa39492cf4dd Bobby Eshleman 2025-11-04 2598 dmabuf_cmsg.frag_token = 45aa39492cf4dd Bobby Eshleman 2025-11-04 2599 tcp_xa_pool.tokens[tcp_xa_pool.idx]; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2600 } else { 45aa39492cf4dd Bobby Eshleman 2025-11-04 2601 token = net_iov_virtual_addr(niov) >> PAGE_SHIFT; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2602 dmabuf_cmsg.frag_token = token; 45aa39492cf4dd Bobby Eshleman 2025-11-04 2603 } 45aa39492cf4dd Bobby Eshleman 2025-11-04 2604 45aa39492cf4dd Bobby Eshleman 2025-11-04 2605 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2606 /* Will perform the exchange later */ 297d389e9e5bd4 Pavel Begunkov 2025-02-04 2607 dmabuf_cmsg.dmabuf_id = net_devmem_iov_binding_id(niov); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2608 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2609 offset += copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2610 remaining_len -= copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2611 18912c520674ec Stanislav Fomichev 2025-02-24 2612 err = put_cmsg_notrunc(msg, SOL_SOCKET, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2613 SO_DEVMEM_DMABUF, 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2614 sizeof(dmabuf_cmsg), 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2615 &dmabuf_cmsg); 18912c520674ec Stanislav Fomichev 2025-02-24 2616 if (err) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2617 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2618 45aa39492cf4dd Bobby Eshleman 2025-11-04 2619 if (sk->sk_devmem_info.autorelease) { 45aa39492cf4dd Bobby Eshleman 2025-11-04 2620 atomic_long_inc(&niov->pp_ref_count); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2621 tcp_xa_pool.netmems[tcp_xa_pool.idx++] = 45aa39492cf4dd Bobby Eshleman 2025-11-04 2622 skb_frag_netmem(frag); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2623 } else { 45aa39492cf4dd Bobby Eshleman 2025-11-04 2624 if (atomic_inc_return(&niov->uref) == 1) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2625 atomic_long_inc(&niov->pp_ref_count); 45aa39492cf4dd Bobby Eshleman 2025-11-04 @2626 refs++; ^^^^^^ 45aa39492cf4dd Bobby Eshleman 2025-11-04 2627 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2628 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2629 sent += copy; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2630 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2631 if (remaining_len == 0) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2632 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2633 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2634 start = end; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2635 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2636 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2637 tcp_xa_pool_commit(sk, &tcp_xa_pool); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2638 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2639 if (!remaining_len) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2640 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2641 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2642 /* if remaining_len is not satisfied yet, we need to go to the 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2643 * next frag in the frag_list to satisfy remaining_len. 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2644 */ 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2645 skb = skb_shinfo(skb)->frag_list ?: skb->next; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2646 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2647 offset = offset - start; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2648 } while (skb); 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2649 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2650 if (remaining_len) { 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2651 err = -EFAULT; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2652 goto out; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2653 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2654 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2655 out: 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2656 tcp_xa_pool_commit(sk, &tcp_xa_pool); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2657 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2658 if (!sent) 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2659 sent = err; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2660 45aa39492cf4dd Bobby Eshleman 2025-11-04 2661 if (refs > 0) 45aa39492cf4dd Bobby Eshleman 2025-11-04 2662 atomic_add(refs, &sk->sk_devmem_info.outstanding_urefs); 45aa39492cf4dd Bobby Eshleman 2025-11-04 2663 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2664 return sent; 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2665 } 8f0b3cc9a4c102 Mina Almasry 2024-09-10 2666 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
