{"id":794,"date":"2026-03-04T15:24:44","date_gmt":"2026-03-04T07:24:44","guid":{"rendered":"https:\/\/hsiang.cc\/?p=794"},"modified":"2026-03-03T15:35:11","modified_gmt":"2026-03-03T07:35:11","slug":"%e9%82%a3%e4%ba%9b%e5%b9%b4%e6%88%91%e8%b8%a9%e9%81%8e%e7%9a%84-memory-leak","status":"publish","type":"post","link":"https:\/\/hsiang.cc\/?p=794","title":{"rendered":"\u90a3\u4e9b\u5e74\u6211\u8e29\u904e\u7684 Memory Leak"},"content":{"rendered":"

\u505a\u5d4c\u5165\u5f0f Linux \u958b\u767c\u90a3\u5e7e\u5e74\uff0cMemory Leak \u5927\u6982\u662f\u6211\u9047\u904e\u6700\u591a\u6b21\u3001\u6700\u96e3\u6293\u3001\u6700\u5bb9\u6613\u88ab\u5ffd\u7565<\/strong>\u7684\u554f\u984c\u3002<\/p>\n

\u684c\u9762\u61c9\u7528\u7a0b\u5f0f\u8a18\u61b6\u9ad4\u6d29\u6f0f\uff0c\u9802\u591a\u8b93\u7a0b\u5f0f\u8dd1\u6162\u3001\u88ab OS \u56de\u6536\u3002\u4f46\u5728\u5d4c\u5165\u5f0f\u7cfb\u7d71\u4e0a\uff0cRAM \u672c\u4f86\u5c31\u4e0d\u591a\uff0c\u4e00\u65e6\u6d29\u6f0f\uff0c\u8f15\u5247\u6548\u80fd\u4e0b\u964d\uff0c\u91cd\u5247\u7cfb\u7d71\u76f4\u63a5 OOM crash\uff0c\u800c\u4e14\u5f80\u5f80\u8981\u8dd1\u597d\u5e7e\u500b\u5c0f\u6642\u624d\u6703\u767c\u4f5c<\/strong>\u3002<\/p>\n

\u9019\u7bc7\u6587\u7ae0\u6574\u7406\u6211\u9019\u5e7e\u5e74\u8e29\u904e\u7684\u5e7e\u500b\u7d93\u5178 Memory Leak \u6848\u4f8b\uff0c\u6bcf\u500b\u90fd\u6709\u9ede\u4e0d\u4e00\u6a23\uff0c\u5e0c\u671b\u80fd\u5e6b\u4f60\u5c11\u8d70\u4e00\u4e9b\u5f4e\u8def\u3002<\/p>\n

\n

\u26a0\ufe0f \u7a0b\u5f0f\u78bc\u70ba\u7c21\u5316\u793a\u610f\u7248\u672c\uff0c\u91cd\u9ede\u5728\u65bc\u5448\u73fe\u554f\u984c\u6a21\u5f0f<\/p>\n<\/blockquote>\n

\n

\u6848\u4f8b\u4e00\uff1a\u6700\u7d93\u5178\u7684\u5fd8\u8a18 free \ud83d\udc23<\/h2>\n

<\/p>\n

\u767c\u751f\u5728\u54ea<\/h3>\n

\u5728\u8def\u7531\u5668\u97cc\u9ad4\u4e0a\u958b\u767c\u4e00\u500b\u8a2d\u5b9a\u6a94\u89e3\u6790\u6a21\u7d44<\/strong>\u3002<\/p>\n

\u554f\u984c\u73fe\u8c61<\/h3>\n

\u7cfb\u7d71\u904b\u884c\u5e7e\u5929\u5f8c\uff0c\u8a18\u61b6\u9ad4\u4f7f\u7528\u91cf\u7de9\u6162\u722c\u5347\uff0c\u6700\u7d42 OOM\u3002<\/p>\n

\u554f\u984c\u7a0b\u5f0f\u78bc<\/h3>\n
\/\/ \u6bcf\u6b21\u6536\u5230 HTTP \u8acb\u6c42\u5c31\u89e3\u6790\u8a2d\u5b9a\nvoid handle_config_request(const char *raw_json) {\n\n    \/\/ \u6bcf\u6b21\u90fd malloc\uff0c\u4f46...\n    config_t *cfg = (config_t *)malloc(sizeof(config_t));\n\n    parse_json(raw_json, cfg);\n    apply_config(cfg);\n\n    \/\/ \u2190 \u5fd8\u8a18 free \u4e86\uff01\n    \/\/ function \u7d50\u675f\uff0ccfg \u6307\u6a19\u6d88\u5931\uff0c\u8a18\u61b6\u9ad4\u6c38\u9060\u56de\u4e0d\u4f86\n}<\/code><\/pre>\n
\u6839\u672c\u539f\u56e0<\/h3>\n
malloc<\/code> \u4e4b\u5f8c\u5fd8\u8a18 free<\/code>\uff0c\u6bcf\u6b21 HTTP \u8acb\u6c42\u90fd\u6d29\u6f0f\u4e00\u584a\u8a18\u61b6\u9ad4\u3002<\/p>\n
\u8acb\u6c42\u91cf\u4e0d\u5927\u6642\u770b\u4e0d\u51fa\u4f86\uff0c\u4f46\u8dd1\u5e7e\u5929\u5c31\u539f\u5f62\u7562\u9732\u3002<\/p>\n
\u4fee\u6b63\u65b9\u5f0f<\/h3>\n
void handle_config_request(const char *raw_json) {\n    config_t *cfg = (config_t *)malloc(sizeof(config_t));\n    if (!cfg) return;  \/\/ \u4e5f\u8981\u8a18\u5f97\u6aa2\u67e5 NULL\uff01\n\n    parse_json(raw_json, cfg);\n    apply_config(cfg);\n\n    free(cfg);         \/\/ \u2705 \u7528\u5b8c\u5c31\u9084\n    cfg = NULL;        \/\/ \u2705 \u907f\u514d dangling pointer\n}<\/code><\/pre>\n
\u6559\u8a13<\/h3>\n
\n
malloc \u548c free \u8981\u50cf\u62ec\u865f\u4e00\u6a23\u6210\u5c0d\u51fa\u73fe\u3002<\/strong>
\n\u5beb\u5b8c malloc \u7684\u4e0b\u4e00\u79d2\uff0c\u5c31\u5148\u628a free \u7684\u4f4d\u7f6e\u60f3\u597d\u3002<\/p>\n<\/blockquote>\n
\n
\u6848\u4f8b\u4e8c\uff1aError Path \u6c92\u6709\u6e05\u7406 \ud83d\ude08<\/h2>\n
\u767c\u751f\u5728\u54ea<\/h3>\n
\u6a21\u7d44\u7684\u7db2\u8def\u9023\u7dda\u521d\u59cb\u5316\u6d41\u7a0b\u3002<\/p>\n
\u554f\u984c\u73fe\u8c61<\/h3>\n
\u7db2\u8def\u9023\u7dda\u5931\u6557<\/strong>\u7684\u60c5\u6cc1\u4e0b\uff0c\u8a18\u61b6\u9ad4\u7de9\u6162\u6d29\u6f0f\u3002<\/p>\n
\u6b63\u5e38\u9023\u7dda\u5b8c\u5168\u6c92\u554f\u984c\uff0c\u53ea\u6709\u5728\u7db2\u8def\u4e0d\u7a69\u3001\u983b\u7e41\u91cd\u9023\u7684\u74b0\u5883\u624d\u6703\u767c\u4f5c\u3002<\/p>\n
\u554f\u984c\u7a0b\u5f0f\u78bc<\/h3>\n
int init_network(network_ctx_t **ctx) {\n\n    *ctx = malloc(sizeof(network_ctx_t));\n\n    (*ctx)->buffer = malloc(BUFFER_SIZE);\n\n    (*ctx)->socket = socket_create();\n    if ((*ctx)->socket < 0) {\n        return -1;  \/\/ \u2190 Error! \u4f46\u4e0a\u9762\u5169\u500b malloc \u6c92\u6709 free\uff01\n    }\n\n    if (connect((*ctx)->socket, ...) < 0) {\n        return -1;  \/\/ \u2190 \u540c\u6a23\u7684\u554f\u984c\n    }\n\n    return 0;\n}<\/code><\/pre>\n
\u6839\u672c\u539f\u56e0<\/h3>\n
Happy Path \u5beb\u5f97\u5f88\u597d\uff0c\u4f46 Error Path \u5b8c\u5168(\u5fd8\u4e86)\u6c92\u6709\u6e05\u7406\u8cc7\u6e90<\/strong>\u3002<\/p>\n
\u9019\u7a2e\u554f\u984c\u7279\u5225\u96b1\u853d\uff0c\u56e0\u70ba\u6b63\u5e38\u6e2c\u8a66\u90fd\u662f\u8d70 Happy Path\uff0cCI \u4e5f\u904e\u4e86\uff0c\u7d50\u679c\u5230\u4e86\u7db2\u8def\u4e0d\u7a69\u7684\u73fe\u5834\u624d\u7206\u767c\u3002<\/p>\n
\u4fee\u6b63\u65b9\u5f0f<\/h3>\n
int init_network(network_ctx_t **ctx) {\n\n    *ctx = malloc(sizeof(network_ctx_t));\n    if (!*ctx) return -1;\n\n    (*ctx)->buffer = malloc(BUFFER_SIZE);\n    if (!(*ctx)->buffer) {\n        goto cleanup_ctx;   \/\/ \u2705 \u7528 goto \u7d71\u4e00\u6e05\u7406\n    }\n\n    (*ctx)->socket = socket_create();\n    if ((*ctx)->socket < 0) {\n        goto cleanup_buffer;\n    }\n\n    if (connect((*ctx)->socket, ...) < 0) {\n        goto cleanup_socket;\n    }\n\n    return 0;\n\n\/\/ \u2705 \u7d71\u4e00\u7684\u6e05\u7406\u5340\u584a\uff0c\u9006\u5e8f\u91cb\u653e\ncleanup_socket:\n    socket_close((*ctx)->socket);\ncleanup_buffer:\n    free((*ctx)->buffer);\ncleanup_ctx:\n    free(*ctx);\n    *ctx = NULL;\n    return -1;\n}<\/code><\/pre>\n
\u6559\u8a13<\/h3>\n
\n
\u6bcf\u689d Error Path \u90fd\u662f\u6f5b\u5728\u7684\u6d29\u6f0f\u9ede\u3002<\/strong>
\nLinux Kernel \u5927\u91cf\u4f7f\u7528 goto cleanup<\/code> \u6a21\u5f0f\uff0c\u4e0d\u662f\u6c92\u6709\u539f\u56e0\u7684\u3002<\/p>\n<\/blockquote>\n
\n
\u6848\u4f8b\u4e09\uff1a\u7b2c\u4e09\u65b9 Library \u7684\u5751 \ud83d\ude24<\/h2>\n
\u767c\u751f\u5728\u54ea<\/h3>\n
\u6574\u5408\u4e00\u500b\u7b2c\u4e09\u65b9\u7684\u5f71\u50cf\u7de8\u89e3\u78bc library\u3002<\/p>\n
\u554f\u984c\u73fe\u8c61<\/h3>\n
\u7cfb\u7d71\u8dd1\u4e45\u4e4b\u5f8c\u8a18\u61b6\u9ad4\u6301\u7e8c\u589e\u9577\uff0c\u4f46\u6211\u628a\u81ea\u5df1\u7684\u7a0b\u5f0f\u78bc\u7ffb\u4e86\u597d\u5e7e\u904d\uff0cmalloc\/free<\/code> \u90fd\u662f\u6210\u5c0d\u7684\uff0c\u627e\u4e0d\u5230\u554f\u984c\u3002<\/p>\n
\u8ffd\u67e5\u904e\u7a0b<\/h3>\n
\u7528 Valgrind \u8dd1\u4e86\u4e00\u6b21\uff1a<\/p>\n
valgrind --leak-check=full \\\n         --show-leak-kinds=all \\\n         --track-origins=yes \\\n         .\/my_program<\/code><\/pre>\n
\u8f38\u51fa\u7d50\u679c\uff1a<\/p>\n
==12345== LEAK SUMMARY:\n==12345==    definitely lost: 2,048 bytes in 1 blocks\n==12345==    indirectly lost: 65,536 bytes in 16 blocks\n==12345==      possibly lost: 0 bytes in 0 blocks\n==12345==    still reachable: 1,024 bytes in 4 blocks\n==12345==\n==12345== 2,048 bytes in 1 blocks are definitely lost\n==12345==    at 0x4C2FB0F: malloc (vg_replace_malloc.c:309)\n==12345==    by 0x401234: codec_init (libcodec.so)   \u2190 \u7b2c\u4e09\u65b9 library\uff01\n==12345==    by 0x402345: my_init_function (main.c:45)<\/code><\/pre>\n
\u6d29\u6f0f\u4f86\u6e90\u662f libcodec.so<\/code>\uff0c\u4e0d\u662f\u6211\u7684\u7a0b\u5f0f\u78bc\u3002<\/p>\n
\u6839\u672c\u539f\u56e0<\/h3>\n
\u7ffb\u4e86 library \u7684\u6587\u4ef6\uff0c\u767c\u73fe\u6709\u4e00\u500b codec_global_cleanup()<\/code> \u51fd\u5f0f\uff0c\u6587\u4ef6\u5beb\u5728\u4e0d\u8d77\u773c\u7684\u89d2\u843d<\/strong>\uff0c\u8aaa\u660e\u7a0b\u5f0f\u7d50\u675f\u524d\u5fc5\u9808\u547c\u53eb\uff0c\u5426\u5247\u6703\u6709\u8cc7\u6e90\u6d29\u6f0f\u3002<\/p>\n
\/\/ \u6587\u4ef6\u4e0a\u5beb\u7684\uff0c\u4f46\u5f88\u5bb9\u6613\u5ffd\u7565\uff1a\n\/\/ "Call codec_global_cleanup() before program exit to release\n\/\/  internal resources allocated during codec_init()"\n\n\/\/ \u6211\u7684\u7a0b\u5f0f\u78bc\u88e1\u5b8c\u5168\u6c92\u6709\u547c\u53eb\u9019\u500b...<\/code><\/pre>\n
\u4fee\u6b63\u65b9\u5f0f<\/h3>\n
int main(void) {\n    codec_init();\n\n    \/\/ ... \u4e3b\u7a0b\u5f0f\u908f\u8f2f ...\n\n    codec_global_cleanup();  \/\/ \u2705 \u88dc\u4e0a\u9019\u884c\n    return 0;\n}<\/code><\/pre>\n
\u6559\u8a13<\/h3>\n
\n
\u6574\u5408\u7b2c\u4e09\u65b9 library\uff0c\u4e00\u5b9a\u8981\u628a\u6587\u4ef6\u5f9e\u982d\u5230\u5c3e\u770b\u4e00\u904d\u3002<\/strong>
\n\u7279\u5225\u6ce8\u610f init\/cleanup<\/code>\u3001create\/destroy<\/code>\u3001open\/close<\/code> \u9019\u985e\u6210\u5c0d\u7684\u51fd\u5f0f\u3002
\nValgrind \u662f\u627e\u51fa\u300c\u662f\u8ab0\u6d29\u6f0f\u300d\u7684\u597d\u5e6b\u624b\u3002<\/p>\n<\/blockquote>\n
\n
\u6848\u4f8b\u56db\uff1a\u8ff4\u5708\u88e1\u7684\u96b1\u85cf\u6d29\u6f0f \ud83d\udd04<\/h2>\n
\u767c\u751f\u5728\u54ea<\/h3>\n
\u8cc7\u6599\u8655\u7406\u7684\u4e3b\u8ff4\u5708\u3002<\/p>\n
\u554f\u984c\u73fe\u8c61<\/h3>\n
\u7cfb\u7d71\u525b\u555f\u52d5\u6642\u8a18\u61b6\u9ad4\u6b63\u5e38\uff0c\u4f46\u8dd1\u5e7e\u500b\u5c0f\u6642\u5f8c\u8a18\u61b6\u9ad4\u5c31\u6eff\u4e86\u3002<\/p>\n
\u554f\u984c\u7a0b\u5f0f\u78bc<\/h3>\n
void data_process_loop(void) {\n    while (1) {\n        \/\/ \u6bcf\u6b21\u8ff4\u5708\u90fd\u5efa\u7acb\u65b0\u7684 buffer\n        uint8_t *process_buf = malloc(PROCESS_BUF_SIZE);\n\n        raw_data_t *raw = malloc(sizeof(raw_data_t));\n\n        read_sensor_data(raw);\n        process_data(raw, process_buf);\n        send_to_display(process_buf);\n\n        free(process_buf);  \/\/ \u2705 \u9019\u500b\u6709 free\n        \/\/ \u2190 raw \u6c92\u6709 free\uff01\u6bcf\u6b21\u8ff4\u5708\u6d29\u6f0f\u4e00\u584a\n\n        vTaskDelay(100 \/ portTICK_PERIOD_MS);\n    }\n}<\/code><\/pre>\n
\u6839\u672c\u539f\u56e0<\/h3>\n
\u8ff4\u5708\u88e1\u6709\u5169\u500b malloc<\/code>\uff0c\u53ea free<\/code> \u4e86\u4e00\u500b\u3002<\/p>\n
\u55ae\u6b21\u6d29\u6f0f\u5f88\u5c0f\uff08\u5e7e\u5341 bytes\uff09\uff0c\u4f46\u8ff4\u5708\u6bcf 100ms \u57f7\u884c\u4e00\u6b21\uff0c\u4e00\u5c0f\u6642\u5c31\u6d29\u6f0f\u5e7e\u842c\u6b21<\/strong>\uff0c\u5e7e\u500b\u5c0f\u6642\u5f8c\u8a18\u61b6\u9ad4\u5c31\u8017\u76e1\u4e86\u3002<\/p>\n
\u4fee\u6b63\u65b9\u5f0f<\/h3>\n
void data_process_loop(void) {\n    \/\/ \u2705 \u56fa\u5b9a\u5927\u5c0f\u7684 buffer \u53ef\u4ee5\u62c9\u5230\u8ff4\u5708\u5916\u9762\uff0c\u53ea malloc \u4e00\u6b21\n    uint8_t *process_buf = malloc(PROCESS_BUF_SIZE);\n    raw_data_t *raw = malloc(sizeof(raw_data_t));\n\n    if (!process_buf || !raw) {\n        \/\/ \u8655\u7406 malloc \u5931\u6557\n        free(process_buf);\n        free(raw);\n        return;\n    }\n\n    while (1) {\n        read_sensor_data(raw);\n        process_data(raw, process_buf);\n        send_to_display(process_buf);\n\n        vTaskDelay(100 \/ portTICK_PERIOD_MS);\n    }\n\n    \/\/ \u7406\u8ad6\u4e0a\u4e0d\u6703\u5230\u9019\u88e1\uff0c\u4f46\u597d\u7fd2\u6163\u9084\u662f\u5beb\u4e0a\n    free(process_buf);\n    free(raw);\n}<\/code><\/pre>\n
\u6559\u8a13<\/h3>\n
\n
\u8ff4\u5708\u88e1\u7684 malloc \u8981\u7279\u5225\u5c0f\u5fc3\u3002<\/strong>
\n\u554f\u81ea\u5df1\uff1a\u300c\u9019\u500b buffer \u771f\u7684\u9700\u8981\u6bcf\u6b21\u91cd\u65b0\u5206\u914d\u55ce\uff1f\u300d
\n\u5982\u679c\u5927\u5c0f\u56fa\u5b9a\uff0c\u62c9\u5230\u8ff4\u5708\u5916\u9762\uff0c\u53ea\u5206\u914d\u4e00\u6b21\u3002<\/p>\n<\/blockquote>\n
\n
\u6848\u4f8b\u4e94\uff1a\u6700\u96e3\u627e\u7684 \u2014 \u9593\u63a5\u6d29\u6f0f \ud83d\udd75\ufe0f<\/h2>\n
\u767c\u751f\u5728\u54ea<\/h3>\n
\u8def\u7531\u5668\u97cc\u9ad4\uff0c\u8a2d\u5b9a\u7ba1\u7406\u6a21\u7d44\u3002<\/p>\n
\u554f\u984c\u73fe\u8c61<\/h3>\n
\u9019\u6b21\u6700\u9ebb\u7169\uff0cValgrind \u5831\u7684\u662f indirectly lost<\/code>\uff0c\u4e0d\u662f definitely lost<\/code>\u3002<\/p>\n
\u554f\u984c\u7a0b\u5f0f\u78bc<\/h3>\n
typedef struct {\n    char *name;      \/\/ \u2190 \u6307\u5411\u52d5\u614b\u5206\u914d\u7684\u5b57\u4e32\n    char *value;     \/\/ \u2190 \u540c\u4e0a\n} config_item_t;\n\ntypedef struct {\n    config_item_t *items;\n    int count;\n} config_list_t;\n\nvoid free_config_list(config_list_t *list) {\n    free(list->items);  \/\/ \u2190 \u53ea free \u4e86 items \u9663\u5217\u672c\u8eab\n    free(list);\n\n    \/\/ \u2190 \u4f46 items[i].name \u548c items[i].value \u6307\u5411\u7684\u5b57\u4e32\u6c92\u6709 free\uff01\n}<\/code><\/pre>\n
\u6839\u672c\u539f\u56e0<\/h3>\n
\u91cb\u653e\u7d50\u69cb\u9ad4\u6642\uff0c\u53ea\u91cb\u653e\u4e86\u300c\u5916\u5c64\u300d\uff0c\u6c92\u6709\u91cb\u653e\u300c\u5167\u5c64\u300d\u6307\u6a19\u6307\u5411\u7684\u8a18\u61b6\u9ad4\u3002<\/p>\n
\u9019\u7a2e\u6d29\u6f0f Valgrind \u6703\u6a19\u8a18\u70ba indirectly lost<\/code>\uff0c\u56e0\u70ba\u6307\u5411\u90a3\u584a\u8a18\u61b6\u9ad4\u7684\u6307\u6a19\u5df2\u7d93\u4e0d\u898b\u4e86\uff08\u96a8\u8457 items<\/code> \u9663\u5217\u88ab free \u800c\u6d88\u5931\uff09\uff0c\u4f46\u8a18\u61b6\u9ad4\u672c\u8eab\u9084\u6c92\u88ab\u91cb\u653e\u3002<\/p>\n
\u4fee\u6b63\u65b9\u5f0f<\/h3>\n
void free_config_list(config_list_t *list) {\n    if (!list) return;\n\n    \/\/ \u2705 \u5148\u91cb\u653e\u5167\u5c64\u7684\u52d5\u614b\u5b57\u4e32\n    for (int i = 0; i < list->count; i++) {\n        free(list->items[i].name);\n        free(list->items[i].value);\n        list->items[i].name = NULL;\n        list->items[i].value = NULL;\n    }\n\n    \/\/ \u2705 \u518d\u91cb\u653e\u5916\u5c64\n    free(list->items);\n    free(list);\n}<\/code><\/pre>\n
\u6559\u8a13<\/h3>\n
\n
\u91cb\u653e\u7d50\u69cb\u9ad4\u4e4b\u524d\uff0c\u5148\u60f3\u60f3\u88e1\u9762\u6709\u6c92\u6709\u6307\u6a19\u3002<\/strong>
\n\u7d50\u69cb\u9ad4\u8d8a\u8907\u96dc\uff0c\u8d8a\u5bb9\u6613\u6f0f\u6389\u5167\u5c64\u7684\u91cb\u653e\u3002
\n\u5efa\u8b70\u70ba\u6bcf\u500b\u8907\u96dc\u7d50\u69cb\u9ad4\u5beb\u4e00\u500b\u5c08\u7528\u7684 destroy<\/code> \u51fd\u5f0f\uff0c\u7d71\u4e00\u7ba1\u7406\u3002<\/p>\n<\/blockquote>\n
\n
\u6211\u7684 Memory Leak \u9810\u9632\u6e05\u55ae \ud83d\udccb<\/h2>\n
\u7d93\u904e\u9019\u4e9b\u5e74\u7684\u6559\u8a13\uff0c\u6211\u6574\u7406\u4e86\u4e00\u4efd\u81ea\u5df1\u5728 Code Review \u6642\u6703\u7528\u7684\u6aa2\u67e5\u6e05\u55ae\uff1a<\/p>\n
\u64b0\u5beb\u7a0b\u5f0f\u78bc\u6642<\/h3>\n