Please check the goto on line 2663. Is an unlock needed here?

julia ---------- Forwarded message ---------- Date: Mon, 12 Apr 2021 01:28:54 +0800 From: kernel test robot <lkp(a)intel.com&gt; To: kbuild(a)lists.01.org Cc: lkp(a)intel.com, Julia Lawall <julia.lawall(a)lip6.fr&gt; Subject: Re: [PATCHv3 bpf-next 1/5] bpf: Allow trampoline re-attach for tracing and lsm programs CC: kbuild-all(a)lists.01.org In-Reply-To: <20210411130010.1337650-2-jolsa(a)kernel.org&gt; References: <20210411130010.1337650-2-jolsa(a)kernel.org&gt; TO: Jiri Olsa <jolsa(a)kernel.org&gt; TO: Alexei Starovoitov <ast(a)kernel.org&gt; TO: Daniel Borkmann <daniel(a)iogearbox.net&gt; TO: Andrii Nakryiko <andriin(a)fb.com&gt; CC: "Toke Høiland-Jørgensen" <toke(a)redhat.com&gt; CC: netdev(a)vger.kernel.org CC: bpf(a)vger.kernel.org CC: Martin KaFai Lau <kafai(a)fb.com&gt; CC: Song Liu <songliubraving(a)fb.com&gt; CC: Yonghong Song <yhs(a)fb.com&gt; CC: John Fastabend <john.fastabend(a)gmail.com&gt; Hi Jiri, I love your patch! Perhaps something to improve: [auto build test WARNING on bpf-next/master] url: https://github.com/0day-ci/linux/commits/Jiri-Olsa/bpf-Tracing-and-lsm-pr... base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master :::::: branch date: 4 hours ago :::::: commit date: 4 hours ago config: x86_64-allyesconfig (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Reported-by: Julia Lawall <julia.lawall(a)lip6.fr&gt; cocci warnings: (new ones prefixed by >>) >> kernel/bpf/syscall.c:2738:1-7: preceding lock on line 2633 vim +2738 kernel/bpf/syscall.c 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2564 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2565 static int bpf_tracing_prog_attach(struct bpf_prog *prog, 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2566 int tgt_prog_fd, 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2567 u32 btf_id) fec56f5890d93f Alexei Starovoitov 2019-11-14 2568 { a3b80e1078943d Andrii Nakryiko 2020-04-28 2569 struct bpf_link_primer link_primer; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2570 struct bpf_prog *tgt_prog = NULL; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2571 struct bpf_trampoline *tr = NULL; 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2572 struct bpf_tracing_link *link; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2573 u64 key = 0; a3b80e1078943d Andrii Nakryiko 2020-04-28 2574 int err; fec56f5890d93f Alexei Starovoitov 2019-11-14 2575 9e4e01dfd3254c KP Singh 2020-03-29 2576 switch (prog->type) { 9e4e01dfd3254c KP Singh 2020-03-29 2577 case BPF_PROG_TYPE_TRACING: fec56f5890d93f Alexei Starovoitov 2019-11-14 2578 if (prog->expected_attach_type != BPF_TRACE_FENTRY && be8704ff07d237 Alexei Starovoitov 2020-01-20 2579 prog->expected_attach_type != BPF_TRACE_FEXIT && 9e4e01dfd3254c KP Singh 2020-03-29 2580 prog->expected_attach_type != BPF_MODIFY_RETURN) { 9e4e01dfd3254c KP Singh 2020-03-29 2581 err = -EINVAL; 9e4e01dfd3254c KP Singh 2020-03-29 2582 goto out_put_prog; 9e4e01dfd3254c KP Singh 2020-03-29 2583 } 9e4e01dfd3254c KP Singh 2020-03-29 2584 break; 9e4e01dfd3254c KP Singh 2020-03-29 2585 case BPF_PROG_TYPE_EXT: 9e4e01dfd3254c KP Singh 2020-03-29 2586 if (prog->expected_attach_type != 0) { 9e4e01dfd3254c KP Singh 2020-03-29 2587 err = -EINVAL; 9e4e01dfd3254c KP Singh 2020-03-29 2588 goto out_put_prog; 9e4e01dfd3254c KP Singh 2020-03-29 2589 } 9e4e01dfd3254c KP Singh 2020-03-29 2590 break; 9e4e01dfd3254c KP Singh 2020-03-29 2591 case BPF_PROG_TYPE_LSM: 9e4e01dfd3254c KP Singh 2020-03-29 2592 if (prog->expected_attach_type != BPF_LSM_MAC) { 9e4e01dfd3254c KP Singh 2020-03-29 2593 err = -EINVAL; 9e4e01dfd3254c KP Singh 2020-03-29 2594 goto out_put_prog; 9e4e01dfd3254c KP Singh 2020-03-29 2595 } 9e4e01dfd3254c KP Singh 2020-03-29 2596 break; 9e4e01dfd3254c KP Singh 2020-03-29 2597 default: fec56f5890d93f Alexei Starovoitov 2019-11-14 2598 err = -EINVAL; fec56f5890d93f Alexei Starovoitov 2019-11-14 2599 goto out_put_prog; fec56f5890d93f Alexei Starovoitov 2019-11-14 2600 } fec56f5890d93f Alexei Starovoitov 2019-11-14 2601 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2602 if (!!tgt_prog_fd != !!btf_id) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2603 err = -EINVAL; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2604 goto out_put_prog; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2605 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2606 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2607 if (tgt_prog_fd) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2608 /* For now we only allow new targets for BPF_PROG_TYPE_EXT */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2609 if (prog->type != BPF_PROG_TYPE_EXT) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2610 err = -EINVAL; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2611 goto out_put_prog; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2612 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2613 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2614 tgt_prog = bpf_prog_get(tgt_prog_fd); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2615 if (IS_ERR(tgt_prog)) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2616 err = PTR_ERR(tgt_prog); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2617 tgt_prog = NULL; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2618 goto out_put_prog; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2619 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2620 22dc4a0f5ed11b Andrii Nakryiko 2020-12-03 2621 key = bpf_trampoline_compute_key(tgt_prog, NULL, btf_id); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2622 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2623 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2624 link = kzalloc(sizeof(*link), GFP_USER); 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2625 if (!link) { 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2626 err = -ENOMEM; 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2627 goto out_put_prog; 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2628 } f2e10bff16a0fd Andrii Nakryiko 2020-04-28 2629 bpf_link_init(&link->link, BPF_LINK_TYPE_TRACING, f2e10bff16a0fd Andrii Nakryiko 2020-04-28 2630 &bpf_tracing_link_lops, prog); f2e10bff16a0fd Andrii Nakryiko 2020-04-28 2631 link->attach_type = prog->expected_attach_type; 70ed506c3bbcfa Andrii Nakryiko 2020-03-02 2632 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 @2633 mutex_lock(&prog->aux->dst_mutex); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2634 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2635 /* There are a few possible cases here: 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2636 * 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2637 * - if prog->aux->dst_trampoline is set, the program was just loaded 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2638 * and not yet attached to anything, so we can use the values stored 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2639 * in prog->aux 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2640 * 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2641 * - if prog->aux->dst_trampoline is NULL, the program has already been 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2642 * attached to a target and its initial target was cleared (below) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2643 * 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2644 * - if tgt_prog != NULL, the caller specified tgt_prog_fd + 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2645 * target_btf_id using the link_create API. 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2646 * 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2647 * - if tgt_prog == NULL when this function was called using the old 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2648 * raw_tracepoint_open API, and we need a target from prog->aux 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2649 * fc909cd5516914 Jiri Olsa 2021-04-11 2650 * - if prog->aux->dst_trampoline and tgt_prog is NULL, the program fc909cd5516914 Jiri Olsa 2021-04-11 2651 * was detached and is going for re-attachment. 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2652 */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2653 if (!prog->aux->dst_trampoline && !tgt_prog) { fc909cd5516914 Jiri Olsa 2021-04-11 2654 /* fc909cd5516914 Jiri Olsa 2021-04-11 2655 * Allow re-attach for TRACING and LSM programs. If it's fc909cd5516914 Jiri Olsa 2021-04-11 2656 * currently linked, bpf_trampoline_link_prog will fail. fc909cd5516914 Jiri Olsa 2021-04-11 2657 * EXT programs need to specify tgt_prog_fd, so they fc909cd5516914 Jiri Olsa 2021-04-11 2658 * re-attach in separate code path. fc909cd5516914 Jiri Olsa 2021-04-11 2659 */ fc909cd5516914 Jiri Olsa 2021-04-11 2660 if (prog->type != BPF_PROG_TYPE_TRACING && fc909cd5516914 Jiri Olsa 2021-04-11 2661 prog->type != BPF_PROG_TYPE_LSM) { fc909cd5516914 Jiri Olsa 2021-04-11 2662 err = -EINVAL; fc909cd5516914 Jiri Olsa 2021-04-11 2663 goto out_put_prog; fc909cd5516914 Jiri Olsa 2021-04-11 2664 } fc909cd5516914 Jiri Olsa 2021-04-11 2665 btf_id = prog->aux->attach_btf_id; fc909cd5516914 Jiri Olsa 2021-04-11 2666 key = bpf_trampoline_compute_key(NULL, prog->aux->attach_btf, btf_id); babf3164095b06 Andrii Nakryiko 2020-03-09 2667 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2668 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2669 if (!prog->aux->dst_trampoline || 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2670 (key && key != prog->aux->dst_trampoline->key)) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2671 /* If there is no saved target, or the specified target is 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2672 * different from the destination specified at load time, we 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2673 * need a new trampoline and a check for compatibility 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2674 */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2675 struct bpf_attach_target_info tgt_info = {}; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2676 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2677 err = bpf_check_attach_target(NULL, prog, tgt_prog, btf_id, 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2678 &tgt_info); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2679 if (err) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2680 goto out_unlock; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2681 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2682 tr = bpf_trampoline_get(key, &tgt_info); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2683 if (!tr) { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2684 err = -ENOMEM; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2685 goto out_unlock; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2686 } 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2687 } else { 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2688 /* The caller didn't specify a target, or the target was the 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2689 * same as the destination supplied during program load. This 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2690 * means we can reuse the trampoline and reference from program 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2691 * load time, and there is no need to allocate a new one. This 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2692 * can only happen once for any program, as the saved values in 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2693 * prog->aux are cleared below. 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2694 */ 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2695 tr = prog->aux->dst_trampoline; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2696 tgt_prog = prog->aux->dst_prog; 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2697 } 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2698 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2699 err = bpf_link_prime(&link->link, &link_primer); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2700 if (err) 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2701 goto out_unlock; fec56f5890d93f Alexei Starovoitov 2019-11-14 2702 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2703 err = bpf_trampoline_link_prog(prog, tr); babf3164095b06 Andrii Nakryiko 2020-03-09 2704 if (err) { a3b80e1078943d Andrii Nakryiko 2020-04-28 2705 bpf_link_cleanup(&link_primer); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2706 link = NULL; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2707 goto out_unlock; fec56f5890d93f Alexei Starovoitov 2019-11-14 2708 } babf3164095b06 Andrii Nakryiko 2020-03-09 2709 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2710 link->tgt_prog = tgt_prog; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2711 link->trampoline = tr; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2712 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2713 /* Always clear the trampoline and target prog from prog->aux to make 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2714 * sure the original attach destination is not kept alive after a 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2715 * program is (re-)attached to another target. 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2716 */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2717 if (prog->aux->dst_prog && 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2718 (tgt_prog_fd || tr != prog->aux->dst_trampoline)) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2719 /* got extra prog ref from syscall, or attaching to different prog */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2720 bpf_prog_put(prog->aux->dst_prog); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2721 if (prog->aux->dst_trampoline && tr != prog->aux->dst_trampoline) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2722 /* we allocated a new trampoline, so free the old one */ 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2723 bpf_trampoline_put(prog->aux->dst_trampoline); 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2724 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2725 prog->aux->dst_prog = NULL; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2726 prog->aux->dst_trampoline = NULL; 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2727 mutex_unlock(&prog->aux->dst_mutex); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2728 a3b80e1078943d Andrii Nakryiko 2020-04-28 2729 return bpf_link_settle(&link_primer); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2730 out_unlock: 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2731 if (tr && tr != prog->aux->dst_trampoline) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2732 bpf_trampoline_put(tr); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2733 mutex_unlock(&prog->aux->dst_mutex); 3aac1ead5eb6b7 Toke Høiland-Jørgensen 2020-09-29 2734 kfree(link); fec56f5890d93f Alexei Starovoitov 2019-11-14 2735 out_put_prog: 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2736 if (tgt_prog_fd && tgt_prog) 4a1e7c0c63e02d Toke Høiland-Jørgensen 2020-09-29 2737 bpf_prog_put(tgt_prog); fec56f5890d93f Alexei Starovoitov 2019-11-14 @2738 return err; fec56f5890d93f Alexei Starovoitov 2019-11-14 2739 } fec56f5890d93f Alexei Starovoitov 2019-11-14 2740 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org