WARNING appears during boot, and the kernel is tainted

Solution In Progress - Updated -

Environment

  • Red Hat Enterprise Linux 8
  • FUJITSU MP1000 system
  • FUJITSU Supercomputer PRIMEHPC FX1000 system
  • FUJITSU Supercomputer PRIMEHPC FX700 system
  • Cray CS500 S3812 system

Issue

  • The following WARNING appears during boot, and the kernel is tainted. Note the following example is from FUJITSU MP1000 system. FUJITSU Supercomputer PRIMEHPC FX1000 / FUJITSU Supercomputer PRIMEHPC FX700 / Cray CS500 S3812 system will have the similar output.
 ------------[ cut here ]------------
  ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (128 < 256)
  WARNING: CPU: 0 PID: 1 at arch/arm64/mm/dma-mapping.c:97 arm64_dma_init+0x54/0xac
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-80.el8.aarch64 #1
  Hardware name: FUJITSU MP1000/CMUA-F      , BIOS 1.0.0 Jul 23 2019
  pstate: 60c00009 (nZCv daif +PAN +UAO)
  pc : arm64_dma_init+0x54/0xac
  lr : arm64_dma_init+0x54/0xac
  sp : ffff00000e6cfda0
  x29: ffff00000e6cfda0 x28: 0000000000000000
  x27: ffff000008f405c4 x26: ffff000009070018
  x25: ffff000008ff1048 x24: ffff000008ed3108
  x23: 0000000000000000 x22: ffff000009069658
  x21: ffff0000093b3708 x20: ffff000008f46ae8
  x19: 00000000000000ee x18: 0000000000000001
  x17: 00000000373874c8 x16: 00000000c9ad9633
  x15: ffffffffffffffff x14: ffff0000093b3708
  x13: ffff000009c164c0 x12: ffff000009c16112
  x11: ffff0000093fe000 x10: ffff00000e6cf9f0
  x9 : ffff00000e6cfda0 x8 : 2038323128204757
  x7 : ffff000009c15000 x6 : 00000000000001e9
  x5 : 00ffffffffffffff x4 : 0000000000000000
  x3 : 0000000000000000 x2 : ffffffffffffffff
  x1 : 5f609462e1c62f00 x0 : 0000000000000000
  Call trace:
   arm64_dma_init+0x54/0xac
   do_one_initcall+0x54/0x1d8
   kernel_init_freeable+0x278/0x314
   kernel_init+0x18/0x110
   ret_from_fork+0x10/0x18
  ---[ end trace 386796d80ec1b3e3 ]---

# cat /proc/sys/kernel/tainted
4

Resolution

  • This is a cosmetic issue as discussed in Red Hat Bugzilla 1715061 and is planned to be addressed in a future kernel release.
  • There is no known impact for the system's normal operation. The users can safely ignore the message and the taint.

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