blocks|key|1947373|text|我也遇到过类似的问题，比如在Android中收集关机日志。我很久以前就发布了这个问题，它有两种方法。我使用第二个，因为第一个对我不起作用。下面是问题所在|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1947374|Where+does+Android+store+shutdown+logs?|offset|length|1947375|希望这能有所帮助。|1947376|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/6071547/shutdown-log-in-android^0|0|0|13|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

I faced a similar issue of collecting shutdown logs in Android. I had posted this question long back and it has 2 approaches. I use the 2nd one as the 1st one doesn't work for me. Here is the question

<a href="https://stackoverflow.com/questions/6071547/shutdown-log-in-android">Where does Android store shutdown logs?</a>

Hope this helps.

blocks|key|1733976|text|/data/dontpanic文件夹怎么样？在内核崩溃发生后，你可以将USB线连接到你的安卓设备上，并通过ADB检查该文件夹中的文件。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1733977|在内核死机后，我发现这个文件夹包含一些apanic文件。例如，如果刚刚发生内核死机，而您去检查文件夹，您可能会找到以下两个文件：|1733978|apanic_console|1733979|apanic_threads|1733980|您可以在apanic_threads中找出发生内核死机时哪个线程/进程正在运行。在apanic_console中，您可能会找到更多信息，如堆栈跟踪和一些关键寄存器的值：PC、LR等。|1733981|它们将帮助您开始调试。|1733982|entityMap^0|0|F|1H|3|0|J|6|0|0|E|0|0|E|0|4|E|15|E|2C|2|2F|2|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|15|8|@$9|16|A|17|B|C]|$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|1E|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|Q|$]]

How about <code>/data/dontpanic</code> folder? After kernel panic happens, you can connect USB cable with your Android device and check the files in that folder through <code>ADB</code>.

I found this folder contains some <code>apanic</code> files after a kernel panic happens. For example, if a kernel panic just happened and you go check the folder, you might find these two files:

<code>apanic_console</code>

<code>apanic_threads</code> 

You can find out in <code>apanic_threads</code> which thread / process is running when the kernel panic happens. In <code>apanic_console</code> you might find out more information such as the stack trace and values of some critical registers: <code>PC</code>, <code>LR</code>, etc. 
They will help you get your debugging started.

blocks|key|1947551|text|对我来说，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1947552|cat+/proc/last_kmsg+|code-block|syntax|javascript|1947553|重新引导后(由insmod期间的内核恐慌引起)是否列出了与崩溃相关的消息，如|1947554|[++424.909515]+Kernel+panic+-+not+syncing:+Fatal+exception
[++424.909606]+Backtrace:+
[++424.909790]+[<c005a5ec>]+(dump_backtrace%2B0x0/0x10c)+from+[<c05f38dc>]+(dump_stack%2B0x18/0x1c)
[++424.909973]++r6:c5cccf00+r5:00000000+r4:c08505a0+r3:00000000|1947555|所以你至少可以试一下。我在Galaxy+Nexus上使用Linux+3.0.31-g4f6d371。|1947556|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

As for me,

<pre><code>cat /proc/last_kmsg 
</code></pre>

after reboot (caused by the kernel panic during insmod) does list messages relevant to the crash, like

<pre><code>[ 424.909515] Kernel panic - not syncing: Fatal exception
[ 424.909606] Backtrace: 
[ 424.909790] [&lt;c005a5ec&gt;] (dump_backtrace+0x0/0x10c) from [&lt;c05f38dc&gt;] (dump_stack+0x18/0x1c)
[ 424.909973] r6:c5cccf00 r5:00000000 r4:c08505a0 r3:00000000
</code></pre>

So you can at least try. I am working with Linux 3.0.31-g4f6d371 on Galaxy Nexus.

blocks|key|1734236|text|Android会创建一个RAM控制台，并尝试将最后一个内核消息缓冲区保存在RAM中(假设不会断电)。您可以通过proc接口访问此文件，并且在我的系统上它是完全可读的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1734237|cat+/proc/last_kmsg|code-block|syntax|javascript|1734238|有关更多信息，请参阅内核代码@+drivers/staging/android/ram_console.c|1734239|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Android creates a RAM console and attempts to save the last kernel message buffer for you in RAM (assuming the power doesn't go out). You can access this file through the proc interface and on my system it is world readable:

<pre><code>cat /proc/last_kmsg
</code></pre>

For more information see the kernel code @ drivers/staging/android/ram_console.c

blocks|key|1734376|text|在Android-7.0或更高版本中，控制台日志被移动到:/sys/fs/pstore/+last_kmesg+-ramoops，所以尝试：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1734377|cat+/sys/fs/pstore/console-ramoops|code-block|syntax|javascript|1734378|它在nexus5x上运行得很好。|1734379|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It seems at Android-7.0 or above, the last_kmesg log is moved to: /sys/fs/pstore/console-ramoops, so try:

<pre><code>cat /sys/fs/pstore/console-ramoops
</code></pre>

it works well for me on nexus-5x

I am using an Android Custom ROM on my device, also with a custom boot.img (custom kernel + cmdline + ramdisk). I now want to be able to view the kernel logs immediately after a kernel panic, but unfortunately I can not use a serial console.

The good news: There seem to be some sources/modules in the Linux kernel of Android that are written exactly for this purpose. For example, the following lines are activated in my .config file for the kernel:

<pre><code>CONFIG_ANDROID_RAM_CONSOLE=y
CONFIG_ANDROID_RAM_CONSOLE_ENABLE_VERBOSE=y
CONFIG_APANIC=y
CONFIG_APANIC_PLABEL="oem_log"
</code></pre>

My problem is: After I forced a kernel panic in order to test this, i.e. by loading a simple panic kernel module with <code>insmod panic.ko</code>, it seems that no log was written to the MTD named oem_log (which exists on my device). Secondly, the RAM also does not contain logs after reboot because it seems to be cleared - or the logs are not written either.

So how can I get the kernel logs after a panic? Also it would be helpful if there is a way I could test the APANIC on the running system. Maybe by using the kernel debug system? As of now I am pretty new to this.

Thanks in advance for any help!

Android: How to get kernel logs after kernel panic?

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我在我的设备上使用了Android Custom ROM，也使用了自定义boot.img (自定义内核+ cmdline +内存磁盘)。我现在希望能够在内核死机后立即查看内核日志，但不幸的是我不能使用串行控制台。好消息是: Android的Linux内核中似乎有一些源代码/模块正是为此目的而编写的。例如，在我的.con...

问Android:内核死机后如何获取内核日志？
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