KERNEL: vmlinux
    DUMPFILE: /home/fedora/vmcore  [PARTIAL DUMP]
        CPUS: 192
	LOAD AVERAGE: 0.05, 0.09, 0.12
       TASKS: 2445
     RELEASE: 3.10.0-327.18.2.el7.ppc64le
     VERSION: #1 SMP Fri Apr 8 05:10:45 EDT 2016
     MACHINE: ppc64le  (3525 Mhz)
      MEMORY: 256 GB
       PANIC: "Unable to handle kernel paging request for data at address 0x00000000"
         PID: 39485
     COMMAND: "rsync"
        TASK: c0000022787bd220  [THREAD_INFO: c000001f06fc0000]
         CPU: 69
       STATE: TASK_RUNNING (PANIC)

--------------------------------------------------------------------------------------------------	   
crash> gdb l*(__d_lookup_rcu+0x150)
0xc000000000327f00 is in __d_lookup_rcu (fs/dcache.c:182).
177     #else
178
179     static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount)
180     {
181             do {
182                     if (*cs != *ct)
183                             return 1;
184                     cs++;
185                     ct++;
186                     tcount--;

--------------------------------------------------------------------------------------------------
crash>dis -l __d_lookup_rcu
...
/usr/src/debug/kernel-3.10.0-327.18.2.el7/linux-3.10.0-327.18.2.el7.ppc64le/fs/dcache.c: 212
0xc000000000327edc <__d_lookup_rcu+300>:        ld      r9,32(r31) 
0xc000000000327ee0 <__d_lookup_rcu+304>:        addi    r9,r9,-1
0xc000000000327ee4 <__d_lookup_rcu+308>:        b       0xc000000000327f00 <__d_lookup_rcu+336>
0xc000000000327ee8 <__d_lookup_rcu+312>:        nop
0xc000000000327eec <__d_lookup_rcu+316>:        nop
0xc000000000327ef0 <__d_lookup_rcu+320>:        nop
0xc000000000327ef4 <__d_lookup_rcu+324>:        nop
0xc000000000327ef8 <__d_lookup_rcu+328>:        nop
0xc000000000327efc <__d_lookup_rcu+332>:        ori     r2,r2,0
/usr/src/debug/kernel-3.10.0-327.18.2.el7/linux-3.10.0-327.18.2.el7.ppc64le/fs/dcache.c: 182
0xc000000000327f00 <__d_lookup_rcu+336>:        lbzu    r7,1(r9)  --->Crash Here(0xc000000000327f00)
0xc000000000327f04 <__d_lookup_rcu+340>:        lbzu    r8,1(r10)
0xc000000000327f08 <__d_lookup_rcu+344>:        cmpw    cr7,r7,r8
0xc000000000327f0c <__d_lookup_rcu+348>:        bne     cr7,0xc000000000327e58 <__d_lookup_rcu+168>

In "/usr/src/debug/kernel-3.10.0-327.18.2.el7/linux-3.10.0-327.18.2.el7.ppc64le/fs/dcache.c: 182", convert to assembly code:
0xc000000000327f00 <__d_lookup_rcu+336>:        lbzu    r7,1(r9)  --->Crash here.(read GPR09 (0xffffffffffffffff +1) = 0x0 , It is a bad address.)

--------------------------------------------------------------------------------------------------
r9: c0000026113203c8 is the address of dentry.d_hash, then struct dentry's address is  0xc0000026113203c0

crash> struct dentry 0xc0000026113203c0
struct dentry {
  d_flags = 17301632,
  d_seq = {
    sequence = 2
  },
  d_hash = {
    next = 0xc0000021b8995dc8,
    pprev = 0xc000003618d25288
  },
  d_parent = 0xc000002611320300,
  d_name = {
    {
      {
        hash = 3566243226,
        len = 8
      },
      hash_len = 37925981594
    },
    name = 0x0      ---> name is NULL
  },
  d_inode = 0xc0000018a8e5fdb8,
  d_iname = "features\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000",	     ---> iname is not NULL
  d_lockref = {
    {
      lock_count = 107374182400,
      {
        lock = {
          {
            rlock = {
              raw_lock = {
                slock = 0
              }
            }
          }
        },
        count = 25
      }
    }
  },
  d_op = 0x0,
  d_sb = 0xc000000fa0a2f800,
  d_time = 0,
  d_fsdata = 0x0,
  d_lru = {
    next = 0xc000002611320380,
    prev = 0xc000002611320500
  },
  d_u = {
    d_child = {
      next = 0xc0000026113203a0,
      prev = 0xc0000026113217d0
    },
    d_rcu = {
      next = 0xc0000026113203a0,
      func = 0xc0000026113217d0
    }
  },
  d_subdirs = {
    next = 0xc000002611321710,
    prev = 0xc000002611320510
  },
  d_alias = {
    next = 0x0,
    pprev = 0xc0000018a8e5fed0
  }
}