ref: 83fe7aaa5ce4776c394cb9edd89189b62efb89a9
parent: e3d8fe9d4a1085cbf7237411bcd1996613334994
author: cinap_lenrek <cinap_lenrek@felloff.net>
date: Mon Oct 23 02:08:18 EDT 2017
upas/smtpd: don't call syslog() from the note handler, this can deadlock when the alarm hits while the process is currently in syslog(), holding the sl lock, then calling syslog again will deadlock: /proc/1729193/text:386 plan 9 executable /sys/lib/acid/port /sys/lib/acid/386 acid: lstk() sleep()+0x7 /sys/src/libc/9syscall/sleep.s:5 lock(lk=0x394d8)+0xb7 /sys/src/libc/port/lock.c:25 i=0x3e8 syslog(logname=0x41c64,cons=0x0,fmt=0x41c6a)+0x2d /sys/src/libc/9sys/syslog.c:60 err=0x79732f27 d=0x0 ctim=0x0 buf=0x0 p=0x0 arg=0x0 n=0x0 catchalarm(msg=0xdfffc854)+0x7a /sys/src/cmd/upas/smtp/smtpd.c:71 notifier+0x30 /sys/src/libc/port/atnotify.c:15