[arch-general] Kernel code dump retrieval
Hello list, I'm experiencing an issue while compiling big projects (i.e. linux kernel but not limited to that). The issue seems to be related to CPUFREQ and I'm trying to track it down. While compiling the linux-ck kernel the kernel panics and produce a core dumps. I'm trying to get the core dump but I'm not able to access it after hard reset. I tried enabling journalctl Storage=Auto to write to disk without luck. My FS is btrfs and the CPU is AMD FX-8120. The CPU is not overclocked [1] and the Cool And Quiet is enabled alond with other power saving options in BIOS (like C6 State). How can I access the kernel core dump after crash? [1] The memory controller is running at 1866MHz Thanks, Leonidas --
Hi
On Thu, Oct 16, 2014 at 4:57 AM, Leonidas Spyropoulos
Hello list,
I'm experiencing an issue while compiling big projects (i.e. linux kernel but not limited to that). The issue seems to be related to CPUFREQ and I'm trying to track it down.
While compiling the linux-ck kernel the kernel panics and produce a core dumps.
When you say "produce a core dumps" what exactly you see. How do you know it produces the kernel dump?
I'm trying to get the core dump but I'm not able to access it after hard reset. I tried enabling journalctl Storage=Auto to write to disk without luck.
After the crash happens kernel cannot write anything to disk nor send via network. Dealing with disk/network/... requires valid kernel data structures and you don't have them anymore. Once kernel crashed it has only one option - reboot.
My FS is btrfs and the CPU is AMD FX-8120. The CPU is not overclocked [1] and the Cool And Quiet is enabled alond with other power saving options in BIOS (like C6 State).
How can I access the kernel core dump after crash?
Check kdump https://wiki.archlinux.org/index.php/Kdump - it is probably what you are looking for.
On 16/10/14, Anatol Pomozov wrote:
When you say "produce a core dumps" what exactly you see. How do you know it produces the kernel dump?
I usually build the AUR package from within X. But sometimes I do it on another TTY. On these cases where I do it from TTY I was able to see partly a core dump (messages about kernel panic and then some more output). The problem was that it was part of it and I could not scroll to see the whole message.
After the crash happens kernel cannot write anything to disk nor send via network. Dealing with disk/network/... requires valid kernel data structures and you don't have them anymore.
Once kernel crashed it has only one option - reboot.
Check kdump https://wiki.archlinux.org/index.php/Kdump - it is probably what you are looking for.
But that invoves a kernel compilation (right?) and I seem to end up in the same problem as before - kernel crashing when compiling big projects. Is there a kernel with Kdump enabled already? --
Hi
On Thu, Oct 16, 2014 at 9:11 AM, Leonidas Spyropoulos
On 16/10/14, Anatol Pomozov wrote:
When you say "produce a core dumps" what exactly you see. How do you know it produces the kernel dump?
I usually build the AUR package from within X. But sometimes I do it on another TTY. On these cases where I do it from TTY I was able to see partly a core dump (messages about kernel panic and then some more output). The problem was that it was part of it and I could not scroll to see the whole message.
So you don't need full kernel memory dump that preserves content of RAM on crash. You just need kernel stack trace message, do you? Check pause_on_oops kernel parameter https://www.kernel.org/doc/Documentation/kernel-parameters.txt it might help you to prevent scrolling. Another option is to use serial port and watch kernel messages from a remote machine https://wiki.archlinux.org/index.php/Working_with_the_serial_console
After the crash happens kernel cannot write anything to disk nor send via network. Dealing with disk/network/... requires valid kernel data structures and you don't have them anymore.
Once kernel crashed it has only one option - reboot.
Check kdump https://wiki.archlinux.org/index.php/Kdump - it is probably what you are looking for.
But that invoves a kernel compilation (right?) and I seem to end up in the same problem as before - kernel crashing when compiling big projects.
Hm... I would recommend you to run memory test to make sure it is not a hardware problem with your RAM.
Is there a kernel with Kdump enabled already?
I do not think so. I was compiling my custom kdump kernel, but it can be done on other machine and then be installed on the problematic machine.
On 16/10/14, Anatol Pomozov wrote:
So you don't need full kernel memory dump that preserves content of RAM on crash. You just need kernel stack trace message, do you?
Check pause_on_oops kernel parameter https://www.kernel.org/doc/Documentation/kernel-parameters.txt it might help you to prevent scrolling. I'll try that first
Another option is to use serial port and watch kernel messages from a remote machine https://wiki.archlinux.org/index.php/Working_with_the_serial_console
Hmm that could take some time to set up.
Hm... I would recommend you to run memory test to make sure it is not a hardware problem with your RAM.
I'll run a Mem stress test. The Corsair Vengeance kit I got suppose to support 1866Mhz through XMP predefined settings - but it's good to validate them.
I do not think so. I was compiling my custom kdump kernel, but it can be done on other machine and then be installed on the problematic machine.
I'll look at the other suggetions first. Thanks, Leonidas --
On 16/10/2014 7:49 μμ, Leonidas Spyropoulos wrote:
On 16/10/14, Anatol Pomozov wrote:
So you don't need full kernel memory dump that preserves content of RAM on crash. You just need kernel stack trace message, do you?
Check pause_on_oops kernel parameter https://www.kernel.org/doc/Documentation/kernel-parameters.txt it might help you to prevent scrolling. I'll try that first
Another option is to use serial port and watch kernel messages from a remote machine https://wiki.archlinux.org/index.php/Working_with_the_serial_console
Hmm that could take some time to set up. You can always try netconsole https://wiki.archlinux.org/index.php/Netconsole It has always managed to capture even the worst kernel panics I have ever had, and its pretty easy to setup
Hm... I would recommend you to run memory test to make sure it is not a hardware problem with your RAM. I'll run a Mem stress test. The Corsair Vengeance kit I got suppose to support 1866Mhz through XMP predefined settings - but it's good to validate them.
I do not think so. I was compiling my custom kdump kernel, but it can be done on other machine and then be installed on the problematic machine. I'll look at the other suggetions first.
Thanks, Leonidas
-- Konstantinos Skarlatos
On 21/10/14, Konstantinos Skarlatos wrote:
You can always try netconsole https://wiki.archlinux.org/index.php/Netconsole It has always managed to capture even the worst kernel panics I have ever had, and its pretty easy to setup
Yeah I've asked in btrfs mailing list also as I thought it was something to do with btrfs and ccache. Got the same answer to set up the netconsole and grab the kernel panic. But at the end it was something else:
I'll run a Mem stress test. The Corsair Vengeance kit I got suppose to support 1866Mhz through XMP predefined settings - but it's good to validate them. After trying different stuff I've figured out I hadn't plugin the extra 4-pin to the motherboard for ATX power. It was after all a hardware issue, and a user specific error!
Thanks for the suggestions though, they are useful for debugging. Cheers, Leonidas --
participants (3)
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Anatol Pomozov
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Konstantinos Skarlatos
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Leonidas Spyropoulos