I updated my seafile instances from 8.0.12 to 8.0.16 on my fully patched Ubuntu 20.04.3 LTS. After the upgrade I find these messages in my /var/log/kern.log
Dec 29 23:47:38 seafile1 kernel: [367340.838659] seaf-server[511776]: segfault at 0 ip 00007f2b1cdd6b82 sp 00007f2b01ff8da8 error 4 in libc-2.31.so[7f2b1cc75000+178000]
Dec 29 23:47:38 seafile1 kernel: [367340.838677] Code: ff ff e9 01 80 f3 ff 90 f3 0f 1e fa 89 f8 31 d2 c5 c5 ef ff 09 f0 25 ff 0f 00 00 3d 80 0f 00 00 0f 8f 52 03 00 00 c5 fe 6f 0f <c5> f5 74 06 c5 fd da c1 c5 fd 74 c7 c5 fd d7 c8 85 c9 74 7a f3 0f
On the backup server:
$ seafile-backup-cmd sync $REPOID
Failed to sync repo $REPOID: Failed to get fs objects from primary.
results on the primary server:
$SERVER-ssl-access.log
$BACKUPIP - - [29/Dec/2021:23:47:38 +0100] "GET /seafhttp/server-sync/repo/$REPOID/info HTTP/1.1" 200 5700 "-" "Seafile/6.0.0 (Linux)"
$BACKUPIP - - [29/Dec/2021:23:47:38 +0100] "GET /seafhttp/repo/$REPOID/commit/HEAD HTTP/1.1" 200 434 "-" "Seafile/6.0.0 (Linux)"
$BACKUPIP - - [29/Dec/2021:23:47:38 +0100] "GET /seafhttp/server-sync/repo/$REPOID/diff/?server-head=f02a0f90b932c841c109928112ccc5d4bfea8519&client-head=9df106f10d61a9e6b738499bbabf70bb270024fc&force=0 HTTP/1.1" 200 374 "-" "Seafile/6.0.0 (Linux)"
$BACKUPIP - - [29/Dec/2021:23:47:38 +0100] "POST /seafhttp/server-sync/repo/$REPOID/multi-fs-id-list/?client-head=9df106f10d61a9e6b738499bbabf70bb270024fc&force=0 HTTP/1.1" 200 527 "-" "Seafile/6.0.0 (Linux)"
$BACKUPIP - - [29/Dec/2021:23:47:38 +0100] "POST /seafhttp/repo/$REPOID/pack-fs/?force=0 HTTP/1.1" 200 24 "-" "Seafile/6.0.0 (Linux)"
$SERVER-ssl-error.log
[Wed Dec 29 23:47:38.993595 2021] [proxy_http:error] [pid 329596:tid 139769560422144] (20014)Internal error (specific information not available): [client $BACKUPIP:55252] AH01102: error reading status line from remote server 127.0.0.1:$PORT
and the crash from above. Downgrading from 8.0.16 to 8.0.12 fixes this problem.