最近接口会偶尔访问502，nginx反向代理，Django web框架。
1、uwsgi的日志：
DAMN ! worker 4 (pid: 27503) died, killed by signal 11 :( trying respawn ...
Respawned uWSGI worker 4 (new pid: 28378)
[2022-05-13 15:05:14][vadmin.op_drf.middleware.process_view():160] [INFO] [] POST:/commit_order/, 权限认证:10
DAMN ! worker 2 (pid: 27501) died, killed by signal 11 :( trying respawn ...
Respawned uWSGI worker 2 (new pid: 28379)
[2022-05-13 15:05:16][vadmin.op_drf.middleware.process_view():160] [INFO] [] POST:/commit_order/, 权限认证:10
DAMN ! worker 3 (pid: 27502) died, killed by signal 11 :( trying respawn ...
Respawned uWSGI worker 3 (new pid: 28380)
[2022-05-13 15:05:17][vadmin.op_drf.middleware.process_view():160] [INFO] [] POST:/commit_order/, 权限认证:10
2、nginx access.log的502日志
221.216.34.70 - - [13/May/2022:15:05:12 +0800] "POST /commit_order/ HTTP/1.1" 502 172 "-" "Dart/2.16 (dart:io)"
221.216.34.70 - - [13/May/2022:15:05:14 +0800] "POST /commit_order/ HTTP/1.1" 502 172 "-" "Dart/2.16 (dart:io)"
221.216.34.70 - - [13/May/2022:15:05:16 +0800] "POST /commit_order/ HTTP/1.1" 502 172 "-" "Dart/2.16 (dart:io)"
3、nginx error.log日志
2022/05/13 11:31:34 [error] 14176#0: *92512 upstream prematurely closed connection while reading response header from upstream, client: 221.216.34.70, server:, request: "POST /order_operation/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:9733", host:
2022/05/13 11:31:38 [error] 14176#0: *92516 upstream prematurely closed connection while reading response header from upstream, client: 221.216.34.70, server:, request: "POST /order_operation/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:9733", host:
2022/05/13 11:31:41 [error] 14176#0: *92516 upstream prematurely closed connection while reading response header from upstream, client: 221.216.34.70, server: , request: "POST /order_operation/ HTTP/1.1", upstream: "uwsgi://127.0.0.1:9733", host: