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#189 stuck while tracing ssi-ksync

v2.0.0pre2
closed-fixed
Roger Tsang
5
2014-08-13
2009-03-28
Roger Tsang
No

From John Hughes (March 16):

# strace -f -o zz /sbin/ssi-ksync
...
pvpop_rmv_child_from_parent: waiting for parent lock 68272
pvpop_rmv_child_from_parent: waiting for parent lock 68272
pvpop_rmv_child_from_parent: waiting for parent lock 68272
pvpop_rmv_child_from_parent: waiting for parent lock 68272
...

Discussion

  • Roger Tsang
    Roger Tsang
    2009-03-28

    From John Hughes (March 16):

    Further investigation shows that the problem is happening in mkdhcpd.conf:

    # strace -f -o zz /sbin/mkdhcpd.conf
    pvpop_rmv_child_from_parent: waiting for parent lock xxxxx

    If I power-off the node that's waiting for the parent lock then the other node crashes:

    Taking over master from node 2.
    Node 2 has gone down!!!
    passed the first scan in ipcname_pull_data
    num_objects[MSG] = 0
    num_objects[SEM] = 0
    num_objects[SHM] = 0
    ipcnameserver ready completed
    write handler down off 2400000 len 4096

    EXT3-fs: INFO: recovery required on readonly filesystem.
    EXT3-fs: write access will be enabled during recovery.
    kjournald starting. Commit interval 5 seconds
    EXT3-fs: recovery complete.
    EXT3-fs: mounted filesystem with ordered data mode.
    fsck 1.37 (21-Mar-2005)
    EXT3 FS on hdb1, internal journal
    /etc/init.d/rc.sysrecover running
    ptrace_unlink: vpop_reclaim failed Unable to handle kernel NULL pointer dereference at virtual address 00000008
    printing eip:
    c0241911
    *pde = 00000000
    Oops: 0000 [#1]
    SMP Modules linked in: parport_pc parport floppy uhci_hcd ohci_hcd ehci_hcd i2c_piix4 i2c_core ide_scsi scsi_mod ext3 jbd ne2k_pci 8390
    CPU: 0
    EIP: 0060:[<c0241911>] Not tainted VLI
    EFLAGS: 00000282 (2.6.11-ssi-686-smp) EIP is at pvpop_reassign_child+0x281/0x920
    eax: 00000000 ebx: 0002074b ecx: 00000000 edx: cea561f0
    esi: 0002074c edi: cf6ae000 ebp: cf6afebc esp: cf6afe1c
    ds: 007b es: 007b ss: 0068
    Process VPROC Slave Dae (pid: 67247, threadinfo=cf6ae000 task=cf980b10)
    Stack: 0002074b 00000001 c04cffc1 00000001 cf6afe4c c01540a2 00000014 00000000 00000000 cf532040 cf532000 00000000 cea561f0 c0155036 cf6afe78 c025c57f 00000001 000008d0 cf9ef700 00000010 cea56cc0 00000001 00000001 cf6afe94 Call Trace:
    [<c010679f>] show_stack+0x7f/0xa0
    [<c0106944>] show_registers+0x164/0x230
    [<c0106cf4>] die+0xf4/0x1c0
    [<c011f39d>] do_page_fault+0x46d/0x669
    [<c0106403>] error_code+0x2b/0x30
    [<c025965a>] vproc_child_lost_parent+0x7a/0x160
    [<c0259ead>] vproc_lost_relations+0xad/0x218
    [<c024d554>] pvpsop_lost_relations+0x94/0xa0
    [<c025956e>] vproc_carelist_cleanup+0x7e/0xf0
    [<c0256933>] vproc_origin_node_cleanup+0x63/0x2b0
    [<c0256dde>] vproc_origin_cleanup+0xbe/0x190
    [<c0257fc1>] vproc_slave_daemon+0x1a1/0x260
    [<c01023a5>] kernel_thread_helper+0x5/0x10
    Code: 8b 4d 8c 89 0c 24 e8 6f a9 01 00 ba 01 00 00 00 89 54 24 04 8b 55 90 8b 42 2c 89 04 24 e8 88 a6 01 00 89 45 8c 8b 4d 8c 8b 55 90 <8b> 41 08 39 42 28 0f 84 12 03 00 00 8b 85 7c ff ff ff 85 c0 75

     
  • Roger Tsang
    Roger Tsang
    2009-07-04

    This pvpop_rmv_child_from_parent() was remotely called from __ptrace_unlink() path and is stuck waiting for lock held by strace process which is waiting for remote child to get reaped.

     
  • Roger Tsang
    Roger Tsang
    2009-07-04

    • milestone: --> v2.0.0pre2
    • assigned_to: nobody --> rogertsang
    • status: open --> open-accepted
     
  • Roger Tsang
    Roger Tsang
    2009-10-27

    checked-in

     
  • Roger Tsang
    Roger Tsang
    2009-10-27

    • status: open-accepted --> open-fixed
     
  • Roger Tsang
    Roger Tsang
    2010-03-13

    • status: open-fixed --> closed-fixed