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Actual challenges

Race condition in kernel

How to cause
  • download vmware image (vmdk disc + vmx config file) with kernel 3.6.11 in development build
    or
    build your own clondike by install manual
  • Start virtual machine
  • The kernel oop appears during system startup
    or
    run update-grub command (may run more than once - it should throw a kernel oops)

How it looks

Nov 24 13:24:39 clondike2 kernel: BUG: unable to handle kernel NULL pointer dereference \
 at 000000000000039f
Nov 24 13:24:39 clondike2 kernel: IP: [] director_task_fork+0x19/0x70
Nov 24 13:24:39 clondike2 kernel: PGD 2b92e067 PUD 2b95d067 PMD 0 
Nov 24 13:24:39 clondike2 kernel: Oops: 0000 [#2] SMP 
Nov 24 13:24:39 clondike2 kernel: Modules linked in:
Nov 24 13:24:39 clondike2 kernel: CPU 0 
Nov 24 13:24:39 clondike2 kernel: Pid: 3776, comm: 10_linux Tainted: G      D W    \
 3.6.11 #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform
Nov 24 13:24:39 clondike2 kernel: RIP: 0010:[]  [] director_task_fork+0x19/0x70
Nov 24 13:24:39 clondike2 kernel: RSP: 0018:ffff88002b92de80  EFLAGS: 00010286
Nov 24 13:24:39 clondike2 kernel: RAX: fffffffffffffdff RBX: ffff88003cafb380 RCX: 0000000000000000
Nov 24 13:24:39 clondike2 kernel: RDX: 0000000000000000 RSI: fffffffffffffdff RDI: ffff88003cafb380
Nov 24 13:24:39 clondike2 kernel: RBP: fffffffffffffdff R08: 00007f3febe069d0 R09: ffffffff8109debf
Nov 24 13:24:39 clondike2 kernel: R10: ffff88003fffefb8 R11: 00000000000153e0 R12: fffffffffffffdff
Nov 24 13:24:39 clondike2 kernel: R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Nov 24 13:24:39 clondike2 kernel: FS:  00007f3febe06700(0000) GS:ffff88003fc00000(0000) \
 knlGS:0000000000000000
Nov 24 13:24:39 clondike2 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Nov 24 13:24:39 clondike2 kernel: CR2: 000000000000039f CR3: 000000002b950000 CR4: 00000000000407b0
Nov 24 13:24:39 clondike2 kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Nov 24 13:24:39 clondike2 kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Nov 24 13:24:39 clondike2 kernel: Process 10_linux (pid: 3776, threadinfo ffff88002b92c000, \
 task ffff88003cafb380)
Nov 24 13:24:39 clondike2 kernel: Stack:
Nov 24 13:24:39 clondike2 kernel: 0000000000000000 fffffffffffffdff 0000000000000000 ffffffff8187cf86
Nov 24 13:24:39 clondike2 kernel: ffffffff8187cf40 fffffffffffffdff 0000000001200011 ffffffff8109f16a
Nov 24 13:24:39 clondike2 kernel: 0000000000000000 0000000003761be4 0000000000000000 00007fff2b5fcbf0
Nov 24 13:24:39 clondike2 kernel: Call Trace:
Nov 24 13:24:39 clondike2 kernel: [] ? tcmi_syscall_hooks_post_fork+0x46/0xb0
Nov 24 13:24:39 clondike2 kernel: [] ? tcmi_syscall_hooks_other_exit+0x30/0x30
Nov 24 13:24:39 clondike2 kernel: [] ? do_fork+0xea/0x3b0
Nov 24 13:24:39 clondike2 kernel: [] ? sys_newstat+0x31/0x50
Nov 24 13:24:39 clondike2 kernel: [] ? stub_clone+0x13/0x20
Nov 24 13:24:39 clondike2 kernel: [] ? system_call_fastpath+0x16/0x1b
Nov 24 13:24:39 clondike2 kernel: Code: 00 00 48 83 ec 08 48 83 c4 08 e9 e3 16 00 00 0f 1f 00 48 \
 83 ec 18 48 85 f6 48 89 5c 24 08 48 89 6c 24 10 48 89 fb 48 89 f5 74 0a <8b> b6 a0 05 00 00 85 f6 \
 74 15 31 c0 48 8b 5c 24 08 48 8b 6c 24 
Nov 24 13:24:39 clondike2 kernel: RIP  [] director_task_fork+0x19/0x70
Nov 24 13:24:39 clondike2 kernel: RSP 
Nov 24 13:24:39 clondike2 kernel: CR2: 000000000000039f
Nov 24 13:24:39 clondike2 kernel: ---[ end trace 6d005f3454fe936c ]---
ċ
kernel_oop.txt
(3k)
novyzde3@fit.cvut.cz,
Dec 4, 2015, 1:27 AM
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