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fix divide by zero when upsync host resolves to no IPv4 address - #329
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ngx_http_upsync_init_server() counts only AF_INET results from getaddrinfo() and then picks one with ngx_random() % n. If the host resolves only to IPv6 (AAAA) addresses, n is 0 and the worker crashes with SIGFPE on every sync attempt. Fall back to the configured address instead, as is already done when getaddrinfo() fails.
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wow, do you still use the module? @gfrankliu |
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Some old systems are still running |
xiaokai-wang
approved these changes
Oct 15, 2026
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ngx_http_upsync_init_server()counts onlyAF_INETresults fromgetaddrinfo()and then picks one withngx_random() % n. If the upsync host resolves only to IPv6 (AAAA) addresses,nis 0 and the worker crashes with SIGFPE (signal 8) on every sync attempt.This falls back to the address resolved at config time (
goto valid), the same path already used whengetaddrinfo()fails. IPv6 support for the upsync connection itself is still out of scope (see #216).