关于文库系统上传文件显示“上传失败 请求出现错误(502 error) T_T”的问题

问题描述：

文件大小3M左右，文件类型PDF，上传配置都已完成见下图：

环境信息：

PHP56、ModStartCMS V8.1.0、文库V3.0.0版本

复现步骤：

上传页面显示如下：

后台一直显示“正在转换”

日志如下：

[2024-02-29 17:48:39] product.INFO: Wenku.WenkuDocProcessJob.start -> 65  
[2024-02-29 17:48:40] product.INFO: Wenku.WenkuDocProcessJob.convert -> 65  
[2024-02-29 17:48:40] product.INFO: Wenku.WenkuDocProcessJob.convert.deletes -> 65 - []  
[2024-02-29 17:48:40] product.INFO: Wenku.WenkuDocProcessJob.convert.start -> 65 - bin  
[2024-02-29 17:48:40] product.INFO: Wenku.BinDocConverterProvider.run    -> pdf2svg "/www/wwwroot/minesoc.com/public/temp/9452df4d2630b3ba24f52ecce4a55635.pdf" "/www/wwwroot/minesoc.com/public/temp/9452df4d2630b3ba24f52ecce4a55635.pdf-%d.svg" all 2>&1  
[2024-02-29 17:48:50] product.INFO: Wenku.BinDocConverterProvider.result -> null  
[2024-02-29 17:48:52] product.INFO: Wenku.WenkuDocProcessJob.convert.end -> 65 - bin - {"code":0,"msg":"ok","data":{"previewType":1,"pageCount":381,"pagePreviews":[],"previewData":{"images":["https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35330_jrcc_3305.svg","https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35331_dktf_3303.svg"],"cover":"https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35330_jrcc_3305.svg"},"fileToClean":["/www/wwwroot/minesoc.com/public/temp/9452df4d2630b3ba24f52ecce4a55635.pdf","/www/wwwroot/minesoc.com/public/temp/9452df4d2630b3ba24f52ecce4a55635.pdf-1.svg","/www/wwwroot/minesoc.com/public/temp/9452df4d2630b3ba24f52ecce4a55635.pdf-2.svg"]}}  
[2024-02-29 17:48:52] product.INFO: Wenku.WenkuDocProcessJob.text -> 65  
[2024-02-29 17:48:52] product.INFO: Wenku.WenkuDocProcessJob.text.data -> {"id":65,"created_at":"2024-02-29 17:48:39","updated_at":"2024-02-29 17:48:39","hash":"z07u8quxlm","memberUserId":1,"categoryId":3,"title":"《煤矿安全生产违法违规行为和处理处罚规范描述汇编》","description":"《煤矿安全生产违法违规行为和处理处罚规范描述汇编》","status":3,"pageCount":381,"viewCount":null,"downloadCount":null,"commentCount":null,"favoriteCount":null,"scoreAvg":null,"creditCost":2,"tags":"","pagePreviews":[],"fileUrl":"https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35319_lqtr_2948.pdf","ext":"pdf","isDeleted":0,"cover":"","convertStatus":1,"previewType":1,"md5":null,"likeCount":null,"moneyCost":"2.00","rateAvg":null,"provider":null,"isRecommend":null,"previewData":{"images":["https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35330_jrcc_3305.svg","https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35331_dktf_3303.svg"],"cover":"https://minesoc-1257295187.cos.ap-chengdu.myqcloud.com/data/file/2024/02/29/35330_jrcc_3305.svg"},"fileSize":4027420,"previewPage":2,"vipFreeDownloadEnable":0,"anonymous":null,"downloadCountBase":87,"favoriteCountBase":64,"likeCountBase":247}