Debug mode kernel

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alvarow
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Debug mode kernel

Unread post by alvarow » Thu Apr 11, 2019 12:24 am

Hello, go my N2 yesterday and got it cranking today! Was able to get it going with the eMMC, pretty snappy!

Upon inspecting dmesg, I noticed this:

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[    0.000000] **********************************************************
[    0.000000] **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
[    0.000000] **                                                      **
[    0.000000] ** trace_printk() being used. Allocating extra memory.  **
[    0.000000] **                                                      **
[    0.000000] ** This means that this is a DEBUG kernel and it is     **
[    0.000000] ** unsafe for production use.                           **
[    0.000000] **                                                      **
[    0.000000] ** If you see this message and you are not debugging    **
[    0.000000] ** the kernel, report this immediately to your vendor!  **
[    0.000000] **                                                      **
[    0.000000] **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
[    0.000000] **********************************************************
I will not be using it as a desktop, rather I am replacing my aging Sheevaplug duties, Webserver, Squid, OpenVPN, Subsonic and Tunnelbroker. Should I expect a production kernel or should I build my own according to the steps on https://wiki.odroid.com/odroid-n2/softw ... d-n2ubuntu ? Any hints on stuff I can safely disable (i.e. turn off everything that states DEBUG in .config?)

Or should I simply not stress about this and just move on and be happy?

Thanks!

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mad_ady
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Re: Debug mode kernel

Unread post by mad_ady » Thu Apr 11, 2019 12:44 am

Don't worry, be happy is my motto.

Most likely the debug kernel will be replaced with a non-debug one in a future update.
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alvarow (Thu Apr 11, 2019 1:40 am)

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tobetter
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Re: Debug mode kernel

Unread post by tobetter » Thu Apr 11, 2019 12:54 am

No harm if ODROID-N2 is really being used for secure production, so it's not being managed to be off so far.
It would be also good to turn off by default and let other developers or contributors turn it on for them? :)
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alvarow (Thu Apr 11, 2019 1:40 am)

alvarow
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Re: Debug mode kernel

Unread post by alvarow » Thu Apr 11, 2019 1:43 am

I am not sure what can be safely turned off, I see there's loads of DEBUG stuff turned ON in

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arch/arm64/configs/odroidn2_defconfig
likely there's stuff that can be safely disabled there. I'll wait and see if a production kernel comes out.

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Re: Debug mode kernel

Unread post by DarkBahamut » Fri Apr 12, 2019 8:59 pm

Having some debug options turned on isn't an issue though and isn't a sign of a non production kernel. Debug options are required for reporting a lot of information into the kernel logs so with them disabled you get literally zero information the second anything goes wrong. Not a situation most device developers or users want to be in.

I checked the the N2's config and see 16 debug options configured.

For comparision, my Galaxy Note 9 (Very much a production device!) has 14 debug options on by default.

Some differences as some options are going to be device specific, but on the whole the number of debug options on are pretty comparable :)

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darkbahamut@ubuntu:~/Desktop/Note9kernelpie$ cat arch/arm64/configs/exynos9810-crownlte_defconfig | grep DEBUG=y
CONFIG_CGROUP_DEBUG=y
CONFIG_SLUB_DEBUG=y
CONFIG_HAVE_DMA_API_DEBUG=y
CONFIG_UH_DEBUG=y
CONFIG_PM_DEBUG=y
CONFIG_PM_SLEEP_DEBUG=y
CONFIG_MMC_DW_DEBUG=y
CONFIG_SEC_DEBUG=y
CONFIG_SEC_PM_DEBUG=y
CONFIG_CMUCAL_DEBUG=y
CONFIG_ARM_EXYNOS_DEVFREQ_DEBUG=y
CONFIG_TRUSTONIC_TEE_DEBUG=y
CONFIG_SDFAT_DEBUG=y
CONFIG_SCHED_DEBUG=y

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