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? Jun 28, 2019 at 23:30
  • I did, results are identical
    – G4Hu
    Jun 28, 2019 at 23:31
  • Identical as in "the kernel is identical and works fine" or as in "I get the same error"? Jun 28, 2019 at 23:35
  • 1
    As in, same errors
    – G4Hu
    Jun 28, 2019 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. Jun 28, 2019 at 23:38


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