Bug 455078

+++ This bug was initially created as a clone of Bug #452501 +++

`strace -f ./vfork' hangs on ia64.
(`-F' is not needed on GNU/Linux, `-f' is enough to trace vfork(2).)

RHEL4-U7-re20080711.0
kernel-2.6.9-78.EL.ia64
strace-4.5.16-1.el4.2.ia64

-- Additional comment from vmayatsk on 2008-06-26 10:35 EST --
This is because IA64 uses clone() instead of vfork(). I played a bit with strace
sources and found that function setbpt() (file util.c) has flag CLONE_VFORK set
in tcp->inst[0] for the case of SYS_clone/clone2, but hasn't it in the case of
SYS_fork/vfork. When I manually remove CLONE_VFORK from inst[0] (case
SYS_clone), strace -f on IA64 works just like as on x86_64. When I manually add
0x4000 (CLONE_VFORK) to arg0 (case SYS_fork) it hangs on x86_64 just like as on
IA64. I'm not an expert in strace, but seems it's a bug in strace utility.

-- Additional comment from jan.kratochvil on 2008-07-08 14:15 EST --
[...]
The ia64 threads fix is unrelated but posted here:
http://sourceforge.net/mailarchive/message.php?msg_name=20080630164049.GA19501%40host0.dyn.jankratochvil.net

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RHEL4-U7-re20080711.0 ia64
kernel-2.6.9-78.EL.ia64
strace-4.5.16-1.el4.2.ia64
$ strace -f ./vfork
...
clone(Process 16684 attached (waiting for parent)
[ hang ]

RHEL4-U7-re20080711.0 ia64
kernel-2.6.9-78.EL.ia64
strace-4.5.16-1.el4.2.ia64 + the patch above
[ This trace was copied from RHEL-5.2 Bug 452501 but it looks the same. ]
$ ./strace -f ./vfork
...
clone(Process 20396 attached
child_stack=0, flags=CLONE_VM|CLONE_VFORK|SIGCHLD) = 20396
[pid 20395] getpid()                    = 20395
...
[pid 20395] write(1, "20396 pid=20395\n", 1620396 pid=20395
) = 16
...
[pid 20395] nanosleep({1, 0},  <unfinished ...>
[pid 20396] write(1, "0 pid=20395\n", 120 pid=20395
) = 12
...
[pid 20396] nanosleep({1, 0},  <unfinished ...>
[pid 20395] <... nanosleep resumed> {1, 0}) = 0
[pid 20395] execve("/bin/true", ["/bin/true"...], [/* 47 vars */] <unfinished ...>
[pid 20396] <... nanosleep resumed> {1, 0}) = 0
[pid 20396] execve("/bin/true", ["/bin/true"...], [/* 47 vars */]) = 1
[pid 20395] <... execve resumed> )      = 1
...
[pid 20395] fstat(3,  <unfinished ...>
[pid 20396] exit_group(0)               = ?
Process 20396 detached
<... fstat resumed> {st_mode=S_IFREG|0644, st_size=58727440, ...}) = 0
--- SIGCHLD (Child exited) @ a000000000010621 (4fac) ---
mmap(NULL, 58727440, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2000000000308000
close(3)                                = 0
close(1)                                = 0
exit_group(0)                           = ?