I have asked this on the mailing list but it seems the list is down right now or something, I tried to post 2 times and it has not shown up. Anyways, it seems that either the qmail-lspawn or qmail-rspawn is dying and causing qmail-send to exit with the error "oh no! lost spawn connection, dying...". I ktraced both qmail spawns and I have come up with this, here is the last 50 lines of both.
qmail-lspawn ktrace output:
23190 qmail-lspawn RET close 0
23190 qmail-lspawn CALL fcntl(0x4,0x2,0x1)
23190 qmail-lspawn RET fcntl 0
23190 qmail-lspawn CALL sigprocmask(0x2,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL select(0x4,0xbfbffd00,0,0,0)
23190 qmail-lspawn RET select 1
23190 qmail-lspawn CALL sigprocmask(0x1,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL read(0x3,0x804d520,0x80)
23190 qmail-lspawn GIO fd 3 read 10 bytes
"did 0+0+1
"
23190 qmail-lspawn RET read 10/0xa
23190 qmail-lspawn CALL sigprocmask(0x2,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL select(0x4,0xbfbffd00,0,0,0)
23190 qmail-lspawn PSIG SIGCHLD caught handler=0x80492a4 mask=0x0 code=0x0
23190 qmail-lspawn RET select -1 errno 4 Interrupted system call
23190 qmail-lspawn CALL wait4(0xffffffff,0xbfbffb10,0x1,0)
23190 qmail-lspawn RET wait4 51093/0xc795
23190 qmail-lspawn CALL close(0x4)
23190 qmail-lspawn RET close 0
23190 qmail-lspawn CALL wait4(0xffffffff,0xbfbffb10,0x1,0)
23190 qmail-lspawn RET wait4 -1 errno 10 No child processes
23190 qmail-lspawn CALL sigreturn(0xbfbffb30)
23190 qmail-lspawn RET sigreturn JUSTRETURN
23190 qmail-lspawn CALL sigprocmask(0x1,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL sigprocmask(0x2,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL select(0x4,0xbfbffd00,0,0,0)
23190 qmail-lspawn RET select 1
23190 qmail-lspawn CALL sigprocmask(0x1,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL read(0x3,0x804d520,0x80)
23190 qmail-lspawn GIO fd 3 read 0 bytes
""
23190 qmail-lspawn RET read 0
23190 qmail-lspawn CALL write(0x1,0x804d9c0,0xe)
23190 qmail-lspawn GIO fd 1 wrote 14 bytes
"\0\0Kdid 0+0+1
\0"
23190 qmail-lspawn RET write 14/0xe
23190 qmail-lspawn CALL close(0x3)
23190 qmail-lspawn RET close 0
23190 qmail-lspawn CALL sigprocmask(0x2,0xbfbffca0,0)
23190 qmail-lspawn RET sigprocmask 0
23190 qmail-lspawn CALL select(0x1,0xbfbffd00,0,0,0)
23190 qmail-lspawn PSIG SIGHUP SIG_DFL
qmail-rspawn ktrace output:
23191 qmail-rspawn CALL read(0x3,0x804c720,0x80)
23191 qmail-rspawn GIO fd 3 read 67 bytes
"r\0K67.28.113.10 accepted message.
Remote host said: 250 ok dirdel
\000"
23191 qmail-rspawn RET read 67/0x43
23191 qmail-rspawn CALL sigprocmask(0x2,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL select(0x4,0xbfbffd10,0,0,0)
23191 qmail-rspawn PSIG SIGCHLD caught handler=0x8048c20 mask=0x0 code=0x0
23191 qmail-rspawn RET select -1 errno 4 Interrupted system call
23191 qmail-rspawn CALL wait4(0xffffffff,0xbfbffb20,0x1,0)
23191 qmail-rspawn RET wait4 46703/0xb66f
23191 qmail-rspawn CALL close(0x4)
23191 qmail-rspawn RET close 0
23191 qmail-rspawn CALL wait4(0xffffffff,0xbfbffb20,0x1,0)
23191 qmail-rspawn RET wait4 -1 errno 10 No child processes
23191 qmail-rspawn CALL sigreturn(0xbfbffb40)
23191 qmail-rspawn RET sigreturn JUSTRETURN
23191 qmail-rspawn CALL sigprocmask(0x1,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL sigprocmask(0x2,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL select(0x4,0xbfbffd10,0,0,0)
23191 qmail-rspawn RET select 1
23191 qmail-rspawn CALL sigprocmask(0x1,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL read(0x3,0x804c720,0x80)
23191 qmail-rspawn GIO fd 3 read 0 bytes
""
23191 qmail-rspawn RET read 0
23191 qmail-rspawn CALL write(0x1,0x804cbc0,0x43)
23191 qmail-rspawn GIO fd 1 wrote 67 bytes
"\0\0K67.28.113.10 accepted message.
Remote host said: 250 ok dirdel
\000"
23191 qmail-rspawn RET write 67/0x43
23191 qmail-rspawn CALL close(0x3)
23191 qmail-rspawn RET close 0
23191 qmail-rspawn CALL sigprocmask(0x2,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL select(0x1,0xbfbffd10,0,0,0)
23191 qmail-rspawn RET select 1
23191 qmail-rspawn CALL sigprocmask(0x1,0xbfbffcb0,0)
23191 qmail-rspawn RET sigprocmask 0
23191 qmail-rspawn CALL read(0,0x804c7a0,0x400)
23191 qmail-rspawn GIO fd 0 read 0 bytes
""
23191 qmail-rspawn RET read 0
23191 qmail-rspawn CALL exit(0)