crash> bt -F
PID: 4581   TASK: ffff881004af1540  CPU: 8   COMMAND: "ll_ost00_070"
 #0 [ffff881004af3cb8] machine_kexec at ffffffff8103915b
    ffff881004af3cc0: 00000000030a1000 ffff8800030a1000
    ffff881004af3cd0: 00000000030a0000 0000000000000000
    ffff881004af3ce0: 8800000000000000 ffff88030c83ffff
    ffff881004af3cf0: 0000000000000000 ffff881004af3d20
    ffff881004af3d00: [size-1024]      [size-256]
    ffff881004af3d10: ffff881004af3de0 crash_kexec+114
 #1 [ffff881004af3d18] crash_kexec at ffffffff810c5e42
    ffff881004af3d20: [size-64]        [size-256]
    ffff881004af3d30: [size-1024]      [size-64]
    ffff881004af3d40: ffff881004af3de0 0000000000000000
    ffff881004af3d50: 0000000000000000 0000000000000001
    ffff881004af3d60: vga_con          0000000000000000
    ffff881004af3d70: 0000000000000001 00000000000027a3
    ffff881004af3d80: 0000000000000000 0000000000000001
    ffff881004af3d90: 0000000000000002 show_trace+21
    ffff881004af3da0: crash_kexec+255  0000000000000010
    ffff881004af3db0: 0000000000000046 ffff881004af3d20
    ffff881004af3dc0: 0000000000000018 0000000000000004
    ffff881004af3dd0: __func__.49560+329 [size-64]
    ffff881004af3de0: ffff881004af3e60 panic+174
 #2 [ffff881004af3de8] panic at ffffffff8152839a
    ffff881004af3df0: lnet_upcall      __func__.49560+329
    ffff881004af3e00: ffffffff00000008 ffff881004af3e70
    ffff881004af3e10: ffff881004af3e20 0000000000000000
    ffff881004af3e20: 0000000033343335 0000000000000282
    ffff881004af3e30: running_helpers_waitq 0000000000000000
    ffff881004af3e40: 0000000000000000 0000000000000000
    ffff881004af3e50: __msg_data.90916 __msg_data.90916
    ffff881004af3e60: ffff881004af3e80 lbug_with_loc+155
 #3 [ffff881004af3e68] lbug_with_loc at ffffffffa0d8ceeb [libcfs]
    ffff881004af3e70: ffff881004b90000 00000000000000a8
    ffff881004af3e80: ffff881004af3e90 osd_key_exit+91
 #4 [ffff881004af3e88] osd_key_exit at ffffffffa14da67b [osd_ldiskfs]
    ffff881004af3e90: ffff881004af3eb0 lu_context_exit+88
 #5 [ffff881004af3e98] lu_context_exit at ffffffffa0e5d9f8 [obdclass]
    ffff881004af3ea0: [size-128]       [size-1024]
    ffff881004af3eb0: ffff881004af3f40 ptlrpc_main+2649
 #6 [ffff881004af3eb8] ptlrpc_main at ffffffffa0ffd749 [ptlrpc]
    ffff881004af3ec0: ffff880400000000 [size-1024]
    ffff881004af3ed0: 0000000000000000 [size-256]
    ffff881004af3ee0: 0000002400000000 [size-1024]
    ffff881004af3ef0: [size-1024]      [size-128]
    ffff881004af3f00: [size-64]        [size-1024]
    ffff881004af3f10: [mm_struct]      [task_struct]
    ffff881004af3f20: 0000000000000000 0000000000000000
    ffff881004af3f30: ptlrpc_main      [size-128]
    ffff881004af3f40: ffff881050ebf6a8 child_rip+10
 #7 [ffff881004af3f48] kernel_thread at ffffffff8100c20a