[t-kristo-pm:usi-5.16-rfc-v2-bpf 18/30] drivers/hid/hid-bpf.c:377:6: warning: variable 'parser' is used uninitialized whenever 'if' condition is true

From: kernel test robot
Date: Fri Nov 26 2021 - 14:44:50 EST

tree: https://github.com/t-kristo/linux-pm usi-5.16-rfc-v2-bpf
head: 241207b4769fca049dfcc4dbde0bda92e4f67027
commit: 940f889f9e4939d1e6701c5e52ed61c1c939ed73 [18/30] HID: bpf: compile fix for bpf_hid_foreach_rdesc_item
config: hexagon-buildonly-randconfig-r002-20211126 (https://download.01.org/0day-ci/archive/20211127/202111270354.U7WXyzuZ-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 5162b558d8c0b542e752b037e72a69d5fd51eb1e)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/t-kristo/linux-pm/commit/940f889f9e4939d1e6701c5e52ed61c1c939ed73
git remote add t-kristo-pm https://github.com/t-kristo/linux-pm
git fetch --no-tags t-kristo-pm usi-5.16-rfc-v2-bpf
git checkout 940f889f9e4939d1e6701c5e52ed61c1c939ed73
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash drivers/hid/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

drivers/hid/hid-bpf.c:142:5: warning: no previous prototype for function 'hid_bpf_prog_detach' [-Wmissing-prototypes]
int hid_bpf_prog_detach(struct hid_device *hdev, struct bpf_prog *prog)
^
drivers/hid/hid-bpf.c:142:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int hid_bpf_prog_detach(struct hid_device *hdev, struct bpf_prog *prog)
^
static
drivers/hid/hid-bpf.c:230:24: warning: no previous prototype for function 'hid_bpf_add_report' [-Wmissing-prototypes]
struct hid_bpf_report *hid_bpf_add_report(struct hid_bpf_parser_and_data *data,
^
drivers/hid/hid-bpf.c:230:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
struct hid_bpf_report *hid_bpf_add_report(struct hid_bpf_parser_and_data *data,
^
static
drivers/hid/hid-bpf.c:258:6: warning: no previous prototype for function 'hid_bpf_free_reports' [-Wmissing-prototypes]
void hid_bpf_free_reports(struct hid_bpf_parser_and_data *data)
^
drivers/hid/hid-bpf.c:258:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void hid_bpf_free_reports(struct hid_bpf_parser_and_data *data)
^
static
drivers/hid/hid-bpf.c:322:7: warning: variable 'ret' is used uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
case HID_MAIN_ITEM_TAG_END_COLLECTION:
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/uapi/linux/hid.h:96:42: note: expanded from macro 'HID_MAIN_ITEM_TAG_END_COLLECTION'
#define HID_MAIN_ITEM_TAG_END_COLLECTION 12
^~
drivers/hid/hid-bpf.c:339:9: note: uninitialized use occurs here
return ret;
^~~
drivers/hid/hid-bpf.c:319:7: warning: variable 'ret' is used uninitialized whenever switch case is taken [-Wsometimes-uninitialized]
case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/uapi/linux/hid.h:95:44: note: expanded from macro 'HID_MAIN_ITEM_TAG_BEGIN_COLLECTION'
#define HID_MAIN_ITEM_TAG_BEGIN_COLLECTION 10
^~
drivers/hid/hid-bpf.c:339:9: note: uninitialized use occurs here
return ret;
^~~
drivers/hid/hid-bpf.c:312:9: note: initialize the variable 'ret' to silence this warning
int ret;
^
= 0
>> drivers/hid/hid-bpf.c:377:6: warning: variable 'parser' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!parser_and_data) {
^~~~~~~~~~~~~~~~
drivers/hid/hid-bpf.c:428:8: note: uninitialized use occurs here
kfree(parser->collection_stack);
^~~~~~
drivers/hid/hid-bpf.c:377:2: note: remove the 'if' if its condition is always false
if (!parser_and_data) {
^~~~~~~~~~~~~~~~~~~~~~~
drivers/hid/hid-bpf.c:356:27: note: initialize the variable 'parser' to silence this warning
struct hid_parser *parser;
^
= NULL
6 warnings generated.


vim +377 drivers/hid/hid-bpf.c

db3fbbad76f810 Benjamin Tissoires 2021-10-13 351
940f889f9e4939 Tero Kristo 2021-11-25 352 BPF_CALL_4(bpf_hid_foreach_rdesc_item, void*, ctx, bpf_callback_t, callback_fn, void *, callback_ctx, u64, flags)
db3fbbad76f810 Benjamin Tissoires 2021-10-13 353 {
db3fbbad76f810 Benjamin Tissoires 2021-10-13 354 struct hid_bpf_ctx *bpf_ctx = ctx;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 355 struct hid_bpf_parser_and_data *parser_and_data;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 356 struct hid_parser *parser;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 357 struct hid_bpf_parser *callback_data;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 358 struct hid_item item;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 359 u8 *data_copy, *start, *end, *next;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 360 u64 cur_index;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 361 u64 ret = 0;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 362 u32 num_elems = 0;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 363
db3fbbad76f810 Benjamin Tissoires 2021-10-13 364 static int (*dispatch_type[])(struct hid_parser *parser,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 365 struct hid_item *item) = {
db3fbbad76f810 Benjamin Tissoires 2021-10-13 366 hid_bpf_parser_main,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 367 hid_parser_global,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 368 hid_parser_local,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 369 hid_parser_reserved
db3fbbad76f810 Benjamin Tissoires 2021-10-13 370 };
db3fbbad76f810 Benjamin Tissoires 2021-10-13 371
db3fbbad76f810 Benjamin Tissoires 2021-10-13 372
db3fbbad76f810 Benjamin Tissoires 2021-10-13 373 if (flags != 0)
db3fbbad76f810 Benjamin Tissoires 2021-10-13 374 return -EINVAL;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 375
db3fbbad76f810 Benjamin Tissoires 2021-10-13 376 parser_and_data = vzalloc(sizeof(*parser_and_data));
db3fbbad76f810 Benjamin Tissoires 2021-10-13 @377 if (!parser_and_data) {
db3fbbad76f810 Benjamin Tissoires 2021-10-13 378 ret = -ENOMEM;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 379 goto exit;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 380 }
db3fbbad76f810 Benjamin Tissoires 2021-10-13 381
db3fbbad76f810 Benjamin Tissoires 2021-10-13 382 parser = &parser_and_data->parser;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 383 callback_data = &parser_and_data->callback_data;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 384
db3fbbad76f810 Benjamin Tissoires 2021-10-13 385 parser->device = bpf_ctx->hdev;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 386
db3fbbad76f810 Benjamin Tissoires 2021-10-13 387 data_copy = kmemdup(bpf_ctx->event.data, HID_BPF_MAX_BUFFER_SIZE, GFP_KERNEL);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 388 if (!data_copy) {
db3fbbad76f810 Benjamin Tissoires 2021-10-13 389 ret = -ENOMEM;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 390 goto exit;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 391 }
db3fbbad76f810 Benjamin Tissoires 2021-10-13 392
db3fbbad76f810 Benjamin Tissoires 2021-10-13 393 start = data_copy;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 394 end = start + bpf_ctx->event.size;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 395
db3fbbad76f810 Benjamin Tissoires 2021-10-13 396 while((next = hid_rdesc_fetch_item(start, end, &item)) != NULL) {
db3fbbad76f810 Benjamin Tissoires 2021-10-13 397 cur_index = start - data_copy;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 398 num_elems++;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 399
db3fbbad76f810 Benjamin Tissoires 2021-10-13 400 dispatch_type[item.type](parser, &item);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 401
db3fbbad76f810 Benjamin Tissoires 2021-10-13 402 hid_bpf_store_bpf_parser(callback_data, &item, parser);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 403
940f889f9e4939 Tero Kristo 2021-11-25 404 ret = callback_fn((u64)(long)ctx, (u64)(long)callback_data,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 405 (u64)(long)&cur_index,
db3fbbad76f810 Benjamin Tissoires 2021-10-13 406 (u64)(long)callback_ctx, 0);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 407 /* return value: 0 - continue, 1 - stop and return */
db3fbbad76f810 Benjamin Tissoires 2021-10-13 408 if (ret)
db3fbbad76f810 Benjamin Tissoires 2021-10-13 409 break;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 410
db3fbbad76f810 Benjamin Tissoires 2021-10-13 411 /* Reset the local parser environment on main items */
db3fbbad76f810 Benjamin Tissoires 2021-10-13 412 if (item.type == HID_ITEM_TYPE_MAIN)
db3fbbad76f810 Benjamin Tissoires 2021-10-13 413 memset(&parser->local, 0, sizeof(parser->local));
db3fbbad76f810 Benjamin Tissoires 2021-10-13 414
db3fbbad76f810 Benjamin Tissoires 2021-10-13 415 /* clear item content */
db3fbbad76f810 Benjamin Tissoires 2021-10-13 416 memset(&item, 0, sizeof(item));
db3fbbad76f810 Benjamin Tissoires 2021-10-13 417
db3fbbad76f810 Benjamin Tissoires 2021-10-13 418 start = next;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 419 }
db3fbbad76f810 Benjamin Tissoires 2021-10-13 420
db3fbbad76f810 Benjamin Tissoires 2021-10-13 421 hid_bpf_free_reports(parser_and_data);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 422
db3fbbad76f810 Benjamin Tissoires 2021-10-13 423 kfree(data_copy);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 424
db3fbbad76f810 Benjamin Tissoires 2021-10-13 425 ret = num_elems;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 426
db3fbbad76f810 Benjamin Tissoires 2021-10-13 427 exit:
db3fbbad76f810 Benjamin Tissoires 2021-10-13 428 kfree(parser->collection_stack);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 429 vfree(parser_and_data);
db3fbbad76f810 Benjamin Tissoires 2021-10-13 430 return ret;
db3fbbad76f810 Benjamin Tissoires 2021-10-13 431 }
db3fbbad76f810 Benjamin Tissoires 2021-10-13 432

:::::: The code at line 377 was first introduced by commit
:::::: db3fbbad76f810554bcb2c098f8c9beb02724702 HID: bpf: add a helper to parse a given report descriptor

:::::: TO: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
:::::: CC: Tero Kristo <tero.kristo@xxxxxxxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx