I am running the latest Raspbian build (Buster). I have compiled a kernel with audit/apparmor support and am trying to boot my Raspberry Pi 4 from it. The kernel is compiled from the latest branch cloned from the GitHub repository. This is resulting in a repeated error during boot:

[x.xxxxxx] raspberrypi-firmware soc:firmware: Coherent DMA mask 0xffffffff (pfn 0xfff40000-0x40000) covers a smaller range of system memory than the DMA zone pfn 0x0-0x80001

I also get other errors I do not understand the cause of:

[x.xxxxxx] bcm2835-cpureq:bcm2835_cpufreq_get_clock:93: Failed to get clock (-12)

[x.xxxxxx] bcm2835_cpufreq: min=0 max=0

[x.xxxxxx] raspberrypi-exp-gpio soc:firmware:gpio: Failed to get GPIO 2 config (-12 82)

[x.xxxxxx] leds-gpio: probe of leds failed with error -12

It ends up hanging after just over a total of 3 seconds into boot with the error:

[x.xxxxxx] Waiting for root device /dev/mmcblk0p2...

What can cause these type of errors?

  • Did you try to build a kernel with no modifications whatsoever? Did it boot? – Dmitry Grigoryev Jun 28 at 23:30
  • I did, results are identical – G4Hu Jun 28 at 23:31
  • Identical as in "the kernel is identical and works fine" or as in "I get the same error"? – Dmitry Grigoryev Jun 28 at 23:35
  • 1
    As in, same errors – G4Hu Jun 28 at 23:35
  • That indicates a problem with the toolchain you use. I suggest you edit your question, explaining how exactly you build that kernel and with what tools. E.g. some versions of GCC are known to produce broken kernels. – Dmitry Grigoryev Jun 28 at 23:38

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