title: How to interpret addresses in a kernel oops
body: <p>I have a kernel oops in a linux device driver I wrote. I want to determine which line is responsible for the oops. I have the following output, but I do not know how to interpret it. </p>
  
  <p>Does it mean my code crashed at the instruction at write_func + 0x63? How can I relate the value in EIP to my own function? What do the values after the backslash mean?</p>
  
  <pre><code>[10991.880354] BUG: unable to handle kernel NULL pointer dereference at   (null)
  [10991.880359] IP: [&lt;c06969d4&gt;] iret_exc+0x7d0/0xa59
  [10991.880365] *pdpt = 000000002258a001 *pde = 0000000000000000
  [10991.880368] Oops: 0002 [#1] PREEMPT SMP
  [10991.880371] last sysfs file: /sys/devices/platform/coretemp.3/temp1_input
  [10991.880374] Modules linked in: nfs lockd fscache nfs_acl auth_rpcgss sunrpc   hdrdmod(F) coretemp(F) af_packet fuse edd cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq mperf microcode dm_mod ppdev sg og3 ghes i2c_i801 igb hed pcspkr iTCO_wdt dca iTCO_vendor_support parport_pc floppy parport ext4 jbd2 crc16 i915 drm_kms_helper drm i2c_algo_bit video button fan processor thermal thermal_sys [last unloaded: preloadtrace]
  [10991.880400]
  [10991.880402] Pid: 4487, comm: python Tainted: GF           2.6.37.1-1.2-desktop #1 To be filled by O.E.M. To be filled by O.E.M./To be filled by O.E.M.
  [10991.880408] EIP: 0060:[&lt;c06969d4&gt;] EFLAGS: 00210246 CPU: 0
  [10991.880411] EIP is at iret_exc+0x7d0/0xa59
  [10991.880413] EAX: 00000000 EBX: 00000000 ECX: 0000018c EDX: b7837000
  [10991.880415] ESI: b7837000 EDI: 00000000 EBP: b7837000 ESP: e2a81ee0
  [10991.880417]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
  [10991.880420] Process python (pid: 4487, ti=e2a80000 task=df940530 task.ti=e2a80000)
  [10991.880422] Stack:
  [10991.880423]  00000000 0000018c 00000000 0000018c e5e903dc e4616353 00000009 df99735c
  [10991.880428]  df900a7c df900a7c b7837000 df80ad80 df99735c 00000009 e46182a4 e2a81f70
  [10991.880433]  e28cd800 e09fc840 e28cd800 fffffffb e09fc888 c03718c1 e4618290 0000018c
  [10991.880438] Call Trace:
  [10991.882006] Inexact backtrace:
  [10991.882006]
  [10991.882012]  [&lt;e4616353&gt;] ? write_func+0x63/0x160 [mymod]
  [10991.882017]  [&lt;c03718c1&gt;] ? proc_file_write+0x71/0xa0
  [10991.882020]  [&lt;c0371850&gt;] ? proc_file_write+0x0/0xa0
  [10991.882023]  [&lt;c036c971&gt;] ? proc_reg_write+0x61/0x90
  [10991.882026]  [&lt;c036c910&gt;] ? proc_reg_write+0x0/0x90
  [10991.882031]  [&lt;c0323060&gt;] ? vfs_write+0xa0/0x160
  [10991.882034]  [&lt;c03243c6&gt;] ? fget_light+0x96/0xb0
  [10991.882037]  [&lt;c0323331&gt;] ? sys_write+0x41/0x70
  [10991.882040]  [&lt;c0202f0c&gt;] ? sysenter_do_call+0x12/0x22
  [10991.882044]  [&lt;c069007b&gt;] ? _lock_kernel+0xab/0x180
  [10991.882046] Code: f3 aa 58 59 e9 5a f9 d7 ff 8d 0c 88 e9 12 fa d7 ff 01 d9 e9 7b fa d7 ff 8d 0c 8b e9 73 fa d7 ff 01 d9 eb 03 8d 0c 8b 51 50 31 c0 &lt;f3&gt; aa 58 59 e9 cf fa d7 ff 01 d9 e9 38 fb d7 ff 8d 0c 8b e9 30
  [10991.882069] EIP: [&lt;c06969d4&gt;] iret_exc+0x7d0/0xa59 SS:ESP 0068:e2a81ee0
  [10991.882072] CR2: 0000000000000000 
  [10991.889660] ---[ end trace 26fe339b54b2ea3e ]---
  </code></pre>