still seeing hangs -- strace

[Eric Whiting]

I still see 2.5.5 hangs where the destination rsync exits (for whatever
reason -- I don't see any errors) and the source waits on something
forever. The interesting thing about it is when I strace the child rsync
pid on the source side then rsync exits as it should.  Strace must
introduce a timing delay of some sort that allows one of the processes
to properly detect the end of channel. I forgot to do a netstat on the
socket this time -- I'll do it next time. I see this hang 3-4 times each
week.

STRACE OF THE PARENT: (does this forever)
----------------------------------------
wait4(7259, 0xbffffc38, WNOHANG, NULL)  = 0
gettimeofday({1028901467, 81808}, NULL) = 0
gettimeofday({1028901467, 81976}, NULL) = 0
select(0, NULL, NULL, NULL, {0, 20000}) = 0 (Timeout)
gettimeofday({1028901467, 101509}, NULL) = 0
select(0, NULL, NULL, NULL, {0, 1000})  = 0 (Timeout)
gettimeofday({1028901467, 111529}, NULL) = 0
wait4(7259, 0xbffffc38, WNOHANG, NULL)  = 0
gettimeofday({1028901467, 111881}, NULL) = 0
gettimeofday({1028901467, 112936}, NULL) = 0
select(0, NULL, NULL, NULL, {0, 20000}) = 0 (Timeout)
gettimeofday({1028901467, 132002}, NULL) = 0
wait4(7259, 0xbffffc38, WNOHANG, NULL)  = 0
gettimeofday({1028901467, 132362}, NULL) = 0

STRACE OF CHILD: this causes rsync to exit properly
---------------------------------------------------
select(7, [3 4], [], NULL, NULL)        = 1 (in [4])
read(4, "", 16384)                      = 0
close(4)                                = 0
select(7, [3], [3], NULL, NULL)         = 1 (out [3])
write(3, "\222\265\316\340q\310\35\244\233T\33\203\5\247~v<\246\5"...,
32) = 32
select(7, [3], [], NULL, NULL)          = 1 (in [3])
read(3, "4\217\321\351`\230\t\32\nx\2150\246\2\352Z\255\33?\314"...,
8192) = 96
close(6)                                = 0
select(7, [3], [3], NULL, NULL)         = 1 (out [3])
write(3, "\361RK\276\257\23u\2265JmI\272(|4\346b.\2760 at k\237-_x\252"...,
32) = 32
ioctl(0, TCGETS, 0xbffffa08)            = -1 EINVAL (Invalid argument)
fcntl64(0, F_GETFL)                     = 0x802 (flags
O_RDWR|O_NONBLOCK)
fcntl64(0, F_SETFL, O_RDWR)             = 0
ioctl(1, TCGETS, 0xbffffa08)            = -1 EINVAL (Invalid argument)
fcntl64(1, F_GETFL)                     = 0x802 (flags
O_RDWR|O_NONBLOCK)
fcntl64(1, F_SETFL, O_RDWR)             = 0
ioctl(2, TCGETS, 0xbffffa08)            = -1 ENOTTY (Inappropriate ioctl
for device)
fcntl64(2, F_GETFL)                     = 0x8801 (flags
O_WRONLY|O_NONBLOCK|O_LARGEFILE)
fcntl64(2, F_SETFL, O_WRONLY|O_LARGEFILE) = 0
gettimeofday({1028901480, 966810}, NULL) = 0
shutdown(3, 2 /* send and receive */)   = 0
close(3)                                = 0
_exit(0)                                = ?


rsync  version 2.5.5  protocol version 26
Copyright (C) 1996-2002 by Andrew Tridgell and others
<http://rsync.samba.org/>
Capabilities: 64-bit files, socketpairs, hard links, symlinks,
batchfiles,
              IPv6, 64-bit system inums, 64-bit internal inums