Re: [PATCH 3/3] HID: bpf: lazy load the hid_tail_call entrypoint

From: Dan Carpenter
Date: Tue Apr 23 2024 - 03:10:26 EST

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In reply to: Benjamin Tissoires: "[PATCH 3/3] HID: bpf: lazy load the hid_tail_call entrypoint"
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Hi Benjamin,

kernel test robot noticed the following build warnings:

url: https://github.com/intel-lab-lkp/linux/commits/Benjamin-Tissoires/HID-bpf-fix-a-comment-in-a-define/20240419-225110
base: b912cf042072e12e93faa874265b30cc0aa521b9
patch link: https://lore.kernel.org/r/20240419-hid_bpf_lazy_skel-v1-3-9210bcd4b61c%40kernel.org
patch subject: [PATCH 3/3] HID: bpf: lazy load the hid_tail_call entrypoint
config: i386-randconfig-141-20240423 (https://download.01.org/0day-ci/archive/20240423/202404231109.h2IRrMMD-lkp@xxxxxxxxx/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)

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 <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202404231109.h2IRrMMD-lkp@xxxxxxxxx/

smatch warnings:
drivers/hid/bpf/hid_bpf_jmp_table.c:478 __hid_bpf_attach_prog() error: uninitialized symbol 'link'.

vim +/link +478 drivers/hid/bpf/hid_bpf_jmp_table.c

f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 396 noinline int
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 397 __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type,
7cdd2108903a4e3 Benjamin Tissoires 2024-01-24 398 int prog_fd, struct bpf_prog *prog, __u32 flags)
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 399 {
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 400 struct bpf_link_primer link_primer;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 401 struct hid_bpf_link *link;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 402 struct hid_bpf_prog_entry *prog_entry;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 403 int cnt, err = -EINVAL, prog_table_idx = -1;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 404
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 405 mutex_lock(&hid_bpf_attach_lock);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 406
60caa381da7dc38 Benjamin Tissoires 2024-04-19 407 if (!jmp_table.map) {
60caa381da7dc38 Benjamin Tissoires 2024-04-19 408 err = hid_bpf_preload_skel();
60caa381da7dc38 Benjamin Tissoires 2024-04-19 409 WARN_ONCE(err, "error while preloading HID BPF dispatcher: %d", err);
60caa381da7dc38 Benjamin Tissoires 2024-04-19 410 if (err)
60caa381da7dc38 Benjamin Tissoires 2024-04-19 411 goto err_unlock;
^^^^^^^^^^^^^^^^
link isn't initialized.

60caa381da7dc38 Benjamin Tissoires 2024-04-19 412 }
60caa381da7dc38 Benjamin Tissoires 2024-04-19 413
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 414 link = kzalloc(sizeof(*link), GFP_USER);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 415 if (!link) {
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 416 err = -ENOMEM;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 417 goto err_unlock;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 418 }
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 419
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 420 bpf_link_init(&link->link, BPF_LINK_TYPE_UNSPEC,
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 421 &hid_bpf_link_lops, prog);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 422
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 423 /* do not attach too many programs to a given HID device */
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 424 cnt = hid_bpf_program_count(hdev, NULL, prog_type);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 425 if (cnt < 0) {
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 426 err = cnt;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 427 goto err_unlock;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 428 }
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 429
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 430 if (cnt >= hid_bpf_max_programs(prog_type)) {
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 431 err = -E2BIG;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 432 goto err_unlock;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 433 }
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 434
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 435 prog_table_idx = hid_bpf_insert_prog(prog_fd, prog);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 436 /* if the jmp table is full, abort */
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 437 if (prog_table_idx < 0) {
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 438 err = prog_table_idx;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 439 goto err_unlock;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 440 }
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 441
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 442 if (flags & HID_BPF_FLAG_INSERT_HEAD) {
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 443 /* take the previous prog_entry slot */
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 444 jmp_table.tail = PREV(jmp_table.tail);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 445 prog_entry = &jmp_table.entries[jmp_table.tail];
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 446 } else {
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 447 /* take the next prog_entry slot */
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 448 prog_entry = &jmp_table.entries[jmp_table.head];
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 449 jmp_table.head = NEXT(jmp_table.head);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 450 }
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 451
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 452 /* we steal the ref here */
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 453 prog_entry->prog = prog;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 454 prog_entry->idx = prog_table_idx;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 455 prog_entry->hdev = hdev;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 456 prog_entry->type = prog_type;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 457
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 458 /* finally store the index in the device list */
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 459 err = hid_bpf_populate_hdev(hdev, prog_type);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 460 if (err) {
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 461 hid_bpf_release_prog_at(prog_table_idx);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 462 goto err_unlock;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 463 }
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 464
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 465 link->hid_table_index = prog_table_idx;
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 466
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 467 err = bpf_link_prime(&link->link, &link_primer);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 468 if (err)
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 469 goto err_unlock;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 470
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 471 mutex_unlock(&hid_bpf_attach_lock);
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 472
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 473 return bpf_link_settle(&link_primer);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 474
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 475 err_unlock:
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 476 mutex_unlock(&hid_bpf_attach_lock);
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 477
4b9a3f49f02bf68 Benjamin Tissoires 2023-01-13 @478 kfree(link);
^^^^

f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 479
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 480 return err;
f5c27da4e3c8a2e Benjamin Tissoires 2022-11-03 481 }

--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Next message: Mingwei Zhang: "Re: [RFC PATCH 23/41] KVM: x86/pmu: Implement the save/restore of PMU state for Intel CPU"
Previous message: Oleksij Rempel: "Re: [PATCH net-next v1 2/4] net: phy: micrel: lan8841: set default PTP latency values"
In reply to: Benjamin Tissoires: "[PATCH 3/3] HID: bpf: lazy load the hid_tail_call entrypoint"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]