Description of problem:
Testcase reparent-zombie-clone can crash the kernel.

Version-Release number of selected component (if applicable):
kernel-2.6.25.4-30.fc9.x86_64

How reproducible:
Always.

Steps to Reproduce:
http://sources.redhat.com/cgi-bin/cvsweb.cgi/~checkout~/tests/ptrace-tests/tests/reparent-zombie-clone.c?cvsroot=systemtap

Actual results:
------------[ cut here ]------------
kernel BUG at include/linux/tracehook.h:345!
invalid opcode: 0000 [1] SMP 
CPU 3 
Modules linked in: bridge bnep rfcomm l2cap bluetooth sunrpc ipv6 loop
dm_multipath sr_mod cdrom pata_acpi ata_piix dcdbas floppy ata_generic iTCO_wdt
pcspkr iTCO_vendor_support serio_raw pata_sil680 libata video output e1000
button sg e752x_edac edac_core joydev dm_snapshot dm_zero dm_mirror dm_mod
shpchp megaraid_mbox megaraid_mm sd_mod scsi_mod ext3 jbd mbcache uhci_hcd
ohci_hcd ehci_hcd [last unloaded: freq_table]
Pid: 5373, comm: reparent-zombie Not tainted 2.6.25.4-30.fc9.x86_64 #1
RIP: 0010:[<ffffffff810358de>]  [<ffffffff810358de>] release_task+0x5c/0x384
RSP: 0018:ffff81003945fdf8  EFLAGS: 00010087
RAX: ffff810039502380 RBX: ffff81002bc62000 RCX: 0000000000000011
RDX: ffff810039502380 RSI: ffff81003945fde8 RDI: ffffffff813f7000
RBP: ffff81003945fe28 R08: 0000000000000004 R09: 0000000000000000
R10: ffffffff8136a2a2 R11: ffff81003945fdb5 R12: ffff81002bc62000
R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff814b61d8
FS:  00007f4395dbc6f0(0000) GS:ffff81003f802c80(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000008f26b0 CR3: 000000002bc99000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process reparent-zombie (pid: 5373, threadinfo ffff81003945e000, task
ffff81002bd48000)
Stack:  ffff81003ac3a3c8 ffff8100394d4000 0000000000000000 ffff81002bd38300
 0000000000000020 ffff81002bd487d8 ffff81003945fe58 ffffffff8106e8c5
 0000000000000000 ffff8100394d4000 000000000007e568 000000000007e568
Call Trace:
 [<ffffffff8106e8c5>] check_dead_utrace+0x168/0x171
 [<ffffffff8106ff01>] wake_quiescent+0x57/0x115
 [<ffffffff81070057>] utrace_detach+0x98/0xa8
 [<ffffffff8103bd08>] ptrace_exit+0x6e/0x151
 [<ffffffff810369cb>] do_exit+0x100/0x656
 [<ffffffff81036fdd>] complete_and_exit+0x0/0x1f
 [<ffffffff8100bedb>] system_call_after_swapgs+0x7b/0x80


Code: 49 8b 84 24 00 04 00 00 f0 ff 48 04 4c 89 e7 e8 b0 f7 0a 00 48 c7 c7 00 70
3f 81 e8 1c b9 25 00 41 83 bc 24 08 02 00 00 20 74 04 <0f> 0b eb fe 49 83 bc 24
c0 07 00 00 00 74 29 49 8d 9c 24 d8 07 
RIP  [<ffffffff810358de>] release_task+0x5c/0x384
 RSP <ffff81003945fdf8>
---[ end trace 90e1f9ce1a0a2fc9 ]---
Fixing recursive fault but reboot is needed!


Expected results:
No crash.