Sunday, February 16, 2014

How to: Generate a kernel log after random reboot

Once in a while, a software bug in the kernel will cause a random reboot, so in order to help kernel developers to fix and troubleshoot the reboots, a kernel log need to be submitted to the developer for further analysis and hopefully lead to a bug fix.

Most Android kernels have "RAM Consoles" to save the necessary kernel logs immediately after reboot in the RAM.  The users can then retrieve this RAM log on a subsequent reboot to submit to kernel developers. Here is a quick tour on how to do that.

[ Using ADB ]
  1. adb shell
  2. su
  3. cat /proc/last_kmsg > /sdcard/last_kmsg.txt
  4. exit
  5. exit
  6. adb pull /sdcard/last_kmsg.txt
File last_kmsg.txt will be located in the same location as adb.exe executable.

[ Using android terminal app ]
  1. su
  2. cat /proc/last_kmsg > /sdcard/last_kmsg.txt
  3. exit
  4. exit
  5. adb pull /sdcard/last_kmsg.txt
File last_kmsg.txt will be located on your SD-card.

[ Using Root Explorer / ES Explorer with Root ]
  1. go to /proc folder
  2. copy last_kmsg to /sdcard/
  3. rename last_kmsg to last_kmsg.txt
File last_kmsg.txt will be located on your SD-card.

The best method to share the last_kmsg.txt content is to upload it to and send a link to the developer.

Source: faux123 (Google +)

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